:root {
  color-scheme: light;
  --background: #f6f7f8;
  --surface: #ffffff;
  --surface-subtle: #f1f3f5;
  --surface-warm: #fff7f3;
  --text-primary: #22262d;
  --text-secondary: #4d535c;
  --text-muted: #646b75;
  --border: #e5e7eb;
  --border-strong: #d3d7dc;
  --brand: #c93c1f;
  --brand-hover: #b4320f;
  --brand-active: #9c2b0c;
  --brand-soft: #fff0ea;
  --brand-ink: #b4320f;
  --success: #13875f;
  --warning: #8a5604;
  --danger: #c93636;
  --info: #2563a9;
  --disabled: #b8bdc5;
  --focus-ring: rgba(242, 85, 49, .28);
  --ink: var(--text-primary);
  --muted: var(--text-secondary);
  --line: var(--border);
  --orange: var(--brand);
  --orange-dark: var(--brand-hover);
  --orange-soft: var(--brand-soft);
  --orange-pale: var(--surface-warm);
  --green: var(--success);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius: var(--radius-md);
  --shadow-sm: 0 6px 20px rgba(24, 29, 37, .06);
  --shadow-md: 0 18px 48px rgba(24, 29, 37, .12);
  --control-height: 44px;
  --header-height: 68px;
  --container: 1160px;
  --motion: 180ms cubic-bezier(.2, .7, .2, 1);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  color: var(--text-primary);
  background: var(--background);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
#app { display: flex; min-height: calc(100vh - var(--header-height)); flex-direction: column; }
#app > .footer { margin-top: auto; }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
button { color: inherit; }
img, video { max-width: 100%; }
[hidden] { display: none !important; }
::selection { color: var(--text-primary); background: #ffd8ca; }
:focus-visible { outline: 3px solid var(--focus-ring); outline-offset: 2px; }
h1[tabindex="-1"]:focus { outline: none; }

.container { width: min(calc(100% - 40px), var(--container)); margin-inline: auto; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-height);
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(14px);
}
.header-inner { display: flex; height: 100%; align-items: center; gap: 40px; }
.brand { display: inline-flex; flex: 0 0 auto; align-items: center; gap: 10px; }
.brand-mark { width: 44px; height: 44px; flex: 0 0 auto; overflow: hidden; border-radius: 10px; background: var(--surface); }
.brand-mark img { width: 100%; height: 100%; object-fit: contain; transform: scale(1.15); }
.brand-copy { display: grid; gap: 2px; line-height: 1; }
.brand-copy strong { font-size: 16px; font-weight: 750; letter-spacing: -.02em; }
.brand-copy small { color: var(--text-muted); font-size: 12px; font-weight: 600; letter-spacing: .1em; }
.desktop-nav { display: flex; align-self: stretch; align-items: center; gap: 28px; }
.desktop-nav a {
  position: relative;
  display: grid;
  height: 100%;
  place-items: center;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  transition: color var(--motion);
}
.desktop-nav a::after { content: ""; position: absolute; right: 50%; bottom: -1px; left: 50%; height: 2px; background: var(--brand); transition: inset var(--motion); }
.desktop-nav a:hover, .desktop-nav a.active { color: var(--text-primary); }
.desktop-nav a.active { font-weight: 650; }
.desktop-nav a.active::after { right: 0; left: 0; }
.header-actions { display: flex; margin-left: auto; align-items: center; gap: 8px; }
.icon-button {
  display: inline-grid;
  width: 40px;
  height: 40px;
  place-items: center;
  border: 0;
  border-radius: var(--radius-sm);
  background: transparent;
  cursor: pointer;
  transition: color var(--motion), background var(--motion);
}
.icon-button:hover { color: var(--brand-ink); background: var(--brand-soft); }
.icon-button:active { background: #ffe5dc; }
.icon-button svg, .search-input-wrap svg, .ui-icon { width: 19px; height: 19px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.8; }
.text-button { padding: 8px; border: 0; color: var(--text-secondary); background: transparent; cursor: pointer; font-size: 13px; }
.text-button:hover { color: var(--brand); }
.text-button:active { color: var(--brand-active); }

.primary-button, .outline-button, .soft-button {
  display: inline-flex;
  min-height: var(--control-height);
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0 20px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-weight: 650;
  font-size: 14px;
  cursor: pointer;
  transition: color var(--motion), background var(--motion), border-color var(--motion), transform var(--motion);
}
.primary-button { color: #fff; background: var(--brand); }
.primary-button:hover { background: var(--brand-hover); }
.primary-button:active { background: var(--brand-active); transform: translateY(1px); }
.primary-button.small { min-height: 38px; padding-inline: 15px; font-size: 13px; }
.outline-button { color: var(--text-primary); border-color: var(--border-strong); background: var(--surface); }
.outline-button:hover { color: var(--brand-ink); border-color: #efae9d; background: var(--surface-warm); }
.soft-button { color: var(--brand-ink); background: var(--brand-soft); }
.soft-button:hover { background: #ffe5dc; }
.primary-button:disabled, .outline-button:disabled, .soft-button:disabled { color: #fff; border-color: var(--border); background: var(--disabled); cursor: not-allowed; transform: none; }
.icon-button:disabled, .text-button:disabled, .filter-chip:disabled, .tab-button:disabled, .lesson-action:disabled { opacity: .48; cursor: not-allowed; }

.eyebrow { margin: 0 0 10px; color: var(--brand); font-size: 11px; font-weight: 750; letter-spacing: .14em; line-height: 1.3; }
.hero { position: relative; min-height: 400px; overflow: hidden; border-bottom: 1px solid var(--border); background: var(--surface); }
.hero::before { display: none; }
.hero-grid { position: relative; display: grid; min-height: 400px; grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr); align-items: center; gap: 48px; }
.hero-copy { max-width: 760px; }
.hero h1 { max-width: 620px; margin: 0; font-size: clamp(42px, 4.4vw, 58px); font-weight: 760; line-height: 1.12; letter-spacing: -.055em; }
.hero h1 span { color: var(--brand); }
.hero-copy > p:not(.eyebrow) { max-width: 570px; margin: 20px 0 0; color: var(--text-secondary); font-size: 16px; line-height: 1.85; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; }
.hero-trust { display: flex; margin-top: 22px; align-items: center; gap: 12px; color: var(--text-secondary); font-size: 12px; }
.avatar-stack { display: flex; padding-left: 7px; }
.avatar-stack i { display: grid; width: 26px; height: 26px; margin-left: -7px; place-items: center; border: 2px solid #fff; border-radius: 50%; color: #fff; background: var(--avatar); font-style: normal; font-size: 12px; font-weight: 700; }
.hero-visual { display: flex; min-height: 350px; align-items: center; justify-content: flex-end; }
.visual-main { width: min(100%, 430px); padding: 26px 28px 22px; border: 1px solid var(--border); border-radius: 18px; background: var(--surface); box-shadow: 0 18px 48px rgba(35,39,47,.08); }
.visual-head { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.visual-head > div { display: grid; gap: 4px; }
.visual-head > div > span { color: var(--brand); font-size: 11px; font-weight: 750; letter-spacing: .08em; }
.visual-head strong { font-size: 18px; font-weight: 720; line-height: 1.35; }
.live-pill { padding: 5px 9px; border-radius: 6px; color: var(--brand-ink); background: var(--brand-soft); font-size: 11px; font-weight: 700; white-space: nowrap; }
.roadmap { display: grid; margin-top: 18px; border-top: 1px solid var(--border); }
.roadmap::before { display: none; }
.roadmap-item { --path-color: var(--brand); --path-bg: var(--brand-soft); display: grid; min-height: 59px; grid-template-columns: 34px minmax(0,1fr) auto; align-items: center; gap: 12px; border-bottom: 1px solid var(--border); }
.roadmap-icon { display: grid; width: 30px; height: 30px; place-items: center; border-radius: 9px; color: var(--path-color); background: var(--path-bg); font-size: 10px; font-weight: 800; }
.roadmap-item.teacher-path { --path-color: #e94a2d; --path-bg: #fff0ec; }
.roadmap-item.family-path { --path-color: #c87315; --path-bg: #fff5e7; }
.roadmap-item.child-path { --path-color: #6650d8; --path-bg: #f1efff; }
.roadmap-item.ai-path { --path-color: #07846a; --path-bg: #e9f8f4; }
.roadmap-copy { min-width: 0; }
.roadmap-copy strong { display: block; overflow: hidden; font-size: 13px; font-weight: 680; text-overflow: ellipsis; white-space: nowrap; }
.roadmap-copy small { display: block; margin-top: 2px; overflow: hidden; color: var(--text-muted); font-size: 11px; text-overflow: ellipsis; white-space: nowrap; }
.roadmap-state { color: var(--path-color); font-size: 11px; font-weight: 650; }
.visual-notes { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 20px; padding-top: 18px; }
.visual-notes > span { display: grid; min-width: 0; grid-template-columns: 30px 1fr; column-gap: 9px; align-items: center; }
.visual-notes i { display: grid; width: 30px; height: 30px; grid-row: 1 / 3; place-items: center; border-radius: 8px; color: var(--brand-ink); background: var(--brand-soft); font-style: normal; font-size: 10px; font-weight: 800; }
.visual-notes b { align-self: end; font-size: 11px; font-weight: 680; }
.visual-notes small { align-self: start; color: var(--text-muted); font-size: 10px; }

.section { padding: 64px 0; }
.section.white { background: var(--surface); }
.section-head { display: flex; margin-bottom: 26px; align-items: end; justify-content: space-between; gap: 32px; }
.section-head h2 { margin: 0; font-size: 28px; font-weight: 720; line-height: 1.28; letter-spacing: -.035em; }
.section-head p { max-width: 640px; margin: 7px 0 0; color: var(--text-secondary); font-size: 14px; }
.section-link { color: var(--text-secondary); font-size: 13px; font-weight: 550; }
.section-link:hover { color: var(--brand); }

.category-strip { display: grid; overflow: hidden; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.category-item { display: grid; min-width: 0; min-height: 104px; place-items: center; align-content: center; gap: 9px; padding: 16px; border-right: 1px solid var(--border); background: transparent; cursor: pointer; transition: color var(--motion), background var(--motion); }
.category-item:last-child { border-right: 0; }
.category-item:hover { color: var(--brand-ink); background: var(--surface-warm); }
.category-item:active { background: var(--brand-soft); }
.category-icon { display: grid; min-width: 34px; height: 34px; place-items: center; border-radius: 8px; color: var(--brand-ink); background: var(--brand-soft); font-size: 13px; font-weight: 750; }
.category-item span:last-child { font-size: 14px; font-weight: 650; }

.course-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.home-course-grid { grid-template-columns: repeat(4, 1fr); }
.core-course-grid { grid-template-columns: repeat(4, 1fr); }
.course-live-section { margin-top: 64px; padding-top: 52px; border-top: 1px solid var(--border); }
.qna-replay-grid { display: grid; grid-template-columns: repeat(4,minmax(0,1fr)); gap: 20px; }
.qna-replay-card { min-width: 0; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); transition: border-color var(--motion), box-shadow var(--motion), transform var(--motion); }
.qna-replay-card:hover { border-color: #efb5a7; box-shadow: var(--shadow-sm); transform: translateY(-2px); }
.qna-replay-card:focus-visible { outline: 3px solid var(--focus-ring); outline-offset: 2px; }
.qna-replay-cover { position: relative; display: flex; height: 144px; flex-direction: column; align-items: flex-start; justify-content: space-between; overflow: hidden; padding: 14px; color: #fff; background: var(--course-gradient); }
.qna-replay-cover::after { position: absolute; inset: 0; content: ""; background: linear-gradient(180deg,rgba(19,22,28,.06),rgba(19,22,28,.42)); pointer-events: none; }
.qna-replay-cover > * { position: relative; z-index: 1; }
.qna-replay-cover .status-pill { color: var(--success); background: rgba(255,255,255,.94); }
.qna-replay-cover small { font-size: 12px; font-weight: 650; }
.qna-play-icon { position: absolute; top: 50%; left: 50%; display: grid; width: 42px; height: 42px; place-items: center; border: 1px solid rgba(255,255,255,.65); border-radius: 50%; background: rgba(20,24,31,.22); box-shadow: 0 6px 20px rgba(20,24,31,.15); transform: translate(-50%,-50%); }
.qna-play-icon .ui-icon { width: 21px; height: 21px; }
.qna-replay-body { padding: 17px; }
.qna-replay-category { color: var(--brand); font-size: 12px; font-weight: 700; }
.qna-replay-body h3 { display: -webkit-box; min-height: 48px; margin: 7px 0 0; overflow: hidden; font-size: 16px; font-weight: 700; line-height: 1.5; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
.qna-replay-body > p { margin: 7px 0 0; color: var(--text-muted); font-size: 12px; }
.qna-replay-body footer { display: flex; margin-top: 15px; padding-top: 13px; align-items: center; justify-content: space-between; gap: 10px; border-top: 1px solid var(--border); }
.qna-replay-body footer span { display: inline-flex; align-items: center; gap: 4px; color: var(--text-muted); font-size: 12px; }
.qna-replay-body footer .ui-icon { width: 14px; height: 14px; }
.qna-replay-body footer strong { color: var(--brand); font-size: 11px; white-space: nowrap; }
.course-card { overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); transition: border-color var(--motion), transform var(--motion); }
.course-card:hover { border-color: #e8a38f; transform: translateY(-2px); }
.course-card:focus-visible { outline-offset: 3px; }
.course-cover { position: relative; display: flex; height: 164px; align-items: flex-end; overflow: hidden; padding: 18px; color: #fff; background: var(--course-gradient); }
.course-cover::before { display: none; }
.course-cover::after { position: absolute; right: 0; bottom: 0; left: 0; height: 46%; content: ""; background: linear-gradient(0deg, rgba(16, 19, 24, .52), rgba(16, 19, 24, 0)); pointer-events: none; }
.cover-glyph { position: absolute; top: 18px; right: 20px; font-size: 42px; font-weight: 800; opacity: .14; transform: none; }
.cover-label { position: relative; display: inline-flex; padding: 4px 8px; border: 1px solid rgba(255,255,255,.25); border-radius: 6px; background: rgba(20,22,26,.32); font-size: 12px; font-weight: 550; }
.course-body { padding: 18px; }
.course-title { min-height: 48px; margin: 0; font-size: 17px; font-weight: 680; line-height: 1.5; }
.course-desc { display: -webkit-box; min-height: 44px; margin: 8px 0 0; overflow: hidden; color: var(--text-secondary); font-size: 13px; line-height: 1.7; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
.course-meta { display: flex; align-items: center; gap: 16px; margin-top: 14px; color: var(--text-muted); font-size: 12px; }
.course-meta span { display: inline-flex; align-items: center; gap: 5px; }
.course-meta .ui-icon { width: 15px; height: 15px; }
.course-footer { display: flex; margin-top: 16px; padding-top: 14px; align-items: center; justify-content: space-between; border-top: 1px solid var(--border); }
.teacher { display: flex; align-items: center; gap: 8px; color: var(--text-secondary); font-size: 12px; }
.teacher-avatar { display: grid; width: 26px; height: 26px; place-items: center; border-radius: 50%; color: #fff; background: var(--course-gradient); font-style: normal; font-size: 12px; font-weight: 700; }
.price { color: var(--brand); font-size: 17px; font-weight: 750; font-variant-numeric: tabular-nums; }
.price.free { color: var(--success); font-size: 13px; }
.badge { display: inline-flex; align-items: center; padding: 4px 8px; border-radius: 6px; font-size: 11px; font-weight: 650; }
.badge.orange { color: var(--brand-ink); background: var(--brand-soft); }
.badge.green { color: var(--success); background: #e9f6f1; }
.badge.gray { color: var(--text-secondary); background: var(--surface-subtle); }
.filter-bar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 24px; }
.filter-chip { display: inline-flex; min-height: 38px; align-items: center; justify-content: center; padding: 0 14px; border: 1px solid var(--border); border-radius: var(--radius-sm); color: var(--text-secondary); background: var(--surface); cursor: pointer; font-size: 13px; transition: color var(--motion), border-color var(--motion), background var(--motion); }
.filter-chip:hover { color: var(--text-primary); border-color: var(--border-strong); }
.filter-chip:active { border-color: #efb3a2; transform: translateY(1px); }
.filter-chip.active { color: var(--brand-ink); border-color: #efb3a2; background: var(--brand-soft); font-weight: 650; }
.filter-tool-link { color: #087c64; border-color: #bcded5; background: #f4fbf8; font-weight: 650; }
.filter-tool-link:hover { color: #05634f; border-color: #78b9a8; background: #eaf7f2; }

.value-banner { display: grid; grid-template-columns: .9fr 1.1fr; align-items: center; gap: 48px; padding: 42px 46px; border-radius: var(--radius-lg); color: #fff; background: #272b33; }
.value-banner h2 { margin: 0; font-size: 30px; line-height: 1.35; letter-spacing: -.025em; }
.value-banner h2 span { color: #ff9a80; }
.value-banner p { margin: 13px 0 0; color: #c0c5cd; font-size: 14px; line-height: 1.8; }
.value-list { display: grid; grid-template-columns: repeat(2, 1fr); overflow: hidden; border: 1px solid rgba(255,255,255,.12); border-radius: var(--radius-md); }
.value-item { display: flex; min-height: 64px; align-items: center; gap: 12px; padding: 14px 16px; border-right: 1px solid rgba(255,255,255,.1); border-bottom: 1px solid rgba(255,255,255,.1); font-size: 13px; }
.value-item:nth-child(2n) { border-right: 0; }
.value-item:nth-last-child(-n+2) { border-bottom: 0; }
.value-item i { color: #ff9a80; font-style: normal; font-size: 11px; font-weight: 750; }

.page-hero { padding: 50px 0 38px; border-bottom: 1px solid var(--border); background: var(--surface); }
.page-hero-grid { display: flex; align-items: flex-end; justify-content: space-between; gap: 32px; }
.page-hero h1 { margin: 0; font-size: 34px; font-weight: 740; line-height: 1.25; letter-spacing: -.04em; }
.page-hero p { max-width: 650px; margin: 11px 0 0; color: var(--text-secondary); font-size: 14px; line-height: 1.8; }
.hero-stat { display: flex; gap: 28px; }
.hero-stat div { min-width: 74px; padding-left: 16px; border-left: 1px solid var(--border); }
.hero-stat strong { display: block; color: var(--brand); font-size: 23px; line-height: 1.2; font-variant-numeric: tabular-nums; }
.hero-stat small { color: var(--text-muted); font-size: 11px; }

.docs-layout { display: grid; grid-template-columns: 210px 1fr; gap: 24px; }
.docs-sidebar { align-self: start; padding: 8px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.docs-sidebar h3 { margin: 7px 10px 10px; font-size: 13px; font-weight: 700; }
.docs-sidebar button { width: 100%; min-height: 40px; padding: 8px 10px; border: 0; border-radius: 7px; text-align: left; color: var(--text-secondary); background: transparent; cursor: pointer; font-size: 13px; }
.docs-sidebar button:hover { color: var(--text-primary); background: var(--surface-subtle); }
.docs-sidebar button.active { color: var(--brand-ink); background: var(--brand-soft); font-weight: 650; }
.docs-content { display: grid; min-width: 0; gap: 28px; }
.docs-list { display: grid; align-self: start; gap: 10px; }
.doc-row { display: grid; grid-template-columns: 44px 1fr auto; align-items: center; gap: 14px; padding: 16px 18px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); transition: border-color var(--motion), background var(--motion); }
.doc-row:hover { border-color: #e8ad9d; background: #fffdfa; }
.doc-row:active { background: var(--surface-warm); }
.doc-icon { display: grid; width: 44px; height: 44px; place-items: center; border-radius: 8px; color: var(--brand-ink); background: var(--brand-soft); font-size: 11px; font-weight: 750; }
.doc-copy h3 { margin: 0; font-size: 15px; font-weight: 650; }
.doc-copy p { margin: 4px 0 0; color: var(--text-muted); font-size: 12px; }
.doc-copy { min-width: 0; }
.doc-action { color: var(--brand); font-size: 12px; font-weight: 600; }
.ai-tools-resource-section .section-head { margin-bottom: 20px; }
.ai-tools-page { min-height: 490px; }
.ai-tools-guide { display: grid; grid-template-columns: auto 1fr; align-items: center; gap: 14px; margin-bottom: 26px; padding: 16px 18px; border-radius: var(--radius-md); color: #fff; background: #292d35; }
.ai-tools-guide > span { padding: 4px 8px; border-radius: 5px; color: #ffded5; background: rgba(255,93,56,.2); font-size: 12px; font-weight: 750; }
.ai-tools-guide p { margin: 0; color: #d4d7dc; font-size: 12px; line-height: 1.6; }
.ai-tool-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 16px; }
.ai-tool-card { position: relative; display: grid; min-width: 0; grid-template-columns: 72px 1fr; align-items: start; gap: 16px; overflow: hidden; padding: 20px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.ai-tool-feature-grid { gap: 22px; }
.ai-tool-feature-grid .ai-tool-card { padding: 26px; box-shadow: 0 10px 30px rgba(29,34,43,.04); }
.ai-tool-feature-grid .ai-tool-card::before { position: absolute; top: 0; right: 0; left: 0; height: 4px; content: ""; background: var(--tool-gradient); }
.ai-tool-feature-grid .ai-tool-icon { width: 82px; height: 82px; }
.ai-tool-feature-grid .ai-tool-copy h3 { font-size: 20px; }
.ai-tool-icon { display: grid; width: 72px; height: 72px; place-items: center; border-radius: 16px; color: #fff; background: var(--tool-gradient); font-size: 16px; font-weight: 800; letter-spacing: -.02em; }
.ai-tool-icon.has-logo, .admin-tool-icon.has-logo { overflow: hidden; padding: 7px; background: #fff; box-shadow: inset 0 0 0 1px rgba(29,34,43,.08); }
.ai-tool-icon.has-logo img, .admin-tool-icon.has-logo img { display: block; width: 100%; height: 100%; object-fit: contain; }
.ai-tool-icon.has-logo img[src$="workbench-logo-official.png"], .admin-tool-icon.has-logo img[src$="workbench-logo-official.png"] { border-radius: 11px; }
.ai-tool-copy { min-width: 0; }
.ai-tool-copy h3 { margin: 9px 0 0; font-size: 18px; font-weight: 720; line-height: 1.4; }
.ai-tool-copy > p { min-height: 66px; margin: 7px 0 0; color: var(--text-secondary); font-size: 12px; line-height: 1.75; }
.ai-tool-meta { display: grid; gap: 3px; margin-top: 12px; color: var(--text-muted); font-size: 12px; }
.ai-tool-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.ai-tool-actions .small-button { min-height: 36px; padding-inline: 13px; font-size: 11px; }
.course-files-stack { display: grid; gap: 28px; }
.course-ai-tools { padding-top: 26px; border-top: 1px solid var(--border); }
.course-ai-tools > div:first-child h3 { margin: 4px 0 0; font-size: 18px; }
.course-ai-tools > div:first-child > p:last-child { margin: 5px 0 16px; color: var(--text-muted); font-size: 11px; }
.ai-tool-grid.compact-grid { grid-template-columns: 1fr; }
.ai-tool-card.compact { grid-template-columns: 54px 1fr; padding: 15px; }
.ai-tool-card.compact .ai-tool-icon { width: 54px; height: 54px; border-radius: 12px; font-size: 12px; }
.ai-tool-card.compact .ai-tool-copy h3 { margin-top: 6px; font-size: 15px; }
.ai-tool-card.compact .ai-tool-copy > p { min-height: auto; font-size: 11px; }

.activate-wrap { display: grid; min-height: calc(100vh - var(--header-height)); place-items: center; padding: 56px 20px 96px; background: var(--background); }
.activate-card { width: min(100%, 500px); padding: 38px; border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface); box-shadow: var(--shadow-sm); text-align: center; }
.activate-icon { display: grid; width: 56px; height: 56px; margin: 0 auto 18px; place-items: center; border-radius: var(--radius-md); color: #fff; background: var(--brand); font-size: 22px; }
.activate-icon .ui-icon { width: 25px; height: 25px; }
.activate-card h1 { margin: 0; font-size: 26px; font-weight: 730; }
.activate-card > p { max-width: 410px; margin: 11px auto 0; color: var(--text-secondary); font-size: 13px; line-height: 1.8; }
.activate-form { margin-top: 26px; }
.activate-form input { width: 100%; height: 50px; padding: 0 15px; border: 1px solid var(--border-strong); border-radius: var(--radius-sm); outline: 0; text-align: center; text-transform: uppercase; letter-spacing: .12em; font-size: 16px; }
.activate-form input::placeholder { color: var(--text-muted); }
.activate-form input:focus { border-color: var(--brand); box-shadow: 0 0 0 3px var(--focus-ring); }
.activate-form input:user-invalid:not(:placeholder-shown) { border-color: var(--danger); box-shadow: 0 0 0 3px rgba(201, 54, 54, .14); }
.activate-form button { width: 100%; margin-top: 10px; }
.demo-tip { margin-top: 16px !important; padding: 9px 10px; border-radius: var(--radius-sm); color: #845d4d !important; background: var(--surface-warm); font-size: 12px !important; }
.benefit-list { display: grid; gap: 10px; margin: 22px 0 0; padding: 20px 0 0; border-top: 1px solid var(--border); text-align: left; }
.benefit-list span { color: var(--text-secondary); font-size: 13px; }
.benefit-list span::before { content: "✓"; display: inline-grid; width: 19px; height: 19px; margin-right: 8px; place-items: center; border-radius: 50%; color: var(--success); background: #e9f6f1; font-size: 12px; font-weight: 800; }

.community-spotlight { display: grid; grid-template-columns: 1fr .82fr; overflow: hidden; margin-bottom: 42px; border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface); }
.spotlight-copy { padding: 36px; color: #fff; background: #292d35; }
.spotlight-copy h2 { margin: 0; font-size: 26px; font-weight: 720; }
.spotlight-copy p { margin: 13px 0 26px; color: #c1c6ce; font-size: 14px; line-height: 1.8; }
.spotlight-stats { display: grid; grid-template-columns: repeat(2, 1fr); }
.spotlight-stats div { display: grid; min-height: 116px; align-content: center; padding: 20px; border-right: 1px solid var(--border); border-bottom: 1px solid var(--border); background: var(--surface); }
.spotlight-stats div:nth-child(2n) { border-right: 0; }
.spotlight-stats div:nth-last-child(-n+2) { border-bottom: 0; }
.spotlight-stats strong { display: block; color: var(--brand); font-size: 22px; font-weight: 730; }
.spotlight-stats span { color: var(--text-secondary); font-size: 12px; }

.course-detail-hero { padding: 44px 0; border-bottom: 1px solid var(--border); background: var(--surface); }
.course-detail-grid { display: grid; grid-template-columns: 400px 1fr; align-items: center; gap: 44px; }
.detail-cover { height: 230px; border-radius: var(--radius-md); }
.detail-copy h1 { margin: 12px 0 0; font-size: 30px; font-weight: 730; line-height: 1.4; letter-spacing: -.025em; }
.detail-copy > p { max-width: 650px; margin: 12px 0 0; color: var(--text-secondary); font-size: 14px; line-height: 1.8; }
.detail-meta { display: flex; flex-wrap: wrap; gap: 18px; margin: 20px 0; color: var(--text-muted); font-size: 12px; }
.detail-meta span { display: inline-flex; align-items: center; gap: 5px; }
.detail-meta .ui-icon { width: 15px; height: 15px; }
.detail-actions { display: flex; align-items: center; gap: 16px; }
.detail-price { color: var(--brand); font-size: 23px; font-weight: 760; font-variant-numeric: tabular-nums; }
.course-content-grid { display: grid; grid-template-columns: 1fr 290px; align-items: start; gap: 22px; }
.content-card { overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.tabs { display: flex; gap: 26px; padding: 0 22px; border-bottom: 1px solid var(--border); }
.tab-button { position: relative; height: 52px; border: 0; color: var(--text-secondary); background: transparent; cursor: pointer; font-size: 13px; }
.tab-button:hover { color: var(--text-primary); }
.tab-button:active { color: var(--brand-active); }
.tab-button.active { color: var(--brand); font-weight: 700; }
.tab-button.active::after { content: ""; position: absolute; right: 0; bottom: -1px; left: 0; height: 2px; background: var(--brand); }
.tab-panel { padding: 22px; }
.lesson-list { display: grid; gap: 6px; }
.lesson-row { display: grid; grid-template-columns: 32px 1fr auto; align-items: center; gap: 12px; min-height: 52px; padding: 10px 12px; border-bottom: 1px solid var(--border); color: var(--text-secondary); font-size: 13px; }
.lesson-row:last-child { border-bottom: 0; }
.lesson-row:hover { background: var(--surface-warm); }
.lesson-index { display: grid; width: 28px; height: 28px; place-items: center; border-radius: 7px; color: var(--text-muted); background: var(--surface-subtle); font-size: 12px; font-variant-numeric: tabular-nums; }
.lesson-action { display: inline-flex; align-items: center; gap: 5px; padding: 7px 8px; border: 0; color: var(--brand); background: transparent; cursor: pointer; font-size: 12px; font-weight: 600; }
.lesson-action.locked { color: var(--text-muted); cursor: not-allowed; }
.lesson-action:not(:disabled):active { color: var(--brand-active); }
.lesson-action .ui-icon { width: 15px; height: 15px; }
.about-copy { max-width: 760px; color: var(--text-secondary); font-size: 14px; line-height: 1.9; }
.side-card { padding: 20px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.side-card h3 { margin: 0 0 14px; font-size: 15px; font-weight: 700; }
.side-card ul { display: grid; gap: 11px; margin: 0; padding: 0; list-style: none; color: var(--text-secondary); font-size: 13px; }
.side-card li::before { content: "✓"; margin-right: 8px; color: var(--success); font-weight: 800; }

.watch-page { min-height: calc(100vh - var(--header-height)); padding: 0 0 88px; background: var(--background); }
.watch-top { height: 48px; color: #aeb4bd; background: #1d2026; font-size: 12px; }
.watch-top .container { display: flex; height: 100%; align-items: center; justify-content: space-between; }
.watch-top a { color: #fff; }
.watch-layout { display: grid; grid-template-columns: minmax(0, 1fr) 320px; align-items: start; gap: 18px; padding-top: 18px; }
.watch-main { min-width: 0; }
.video-frame { position: relative; display: grid; width: 100%; aspect-ratio: 16 / 9; overflow: hidden; place-items: center; border-radius: var(--radius-md); background: #080a0d; box-shadow: var(--shadow-sm); }
.course-video { width: 100%; height: 100%; object-fit: contain; background: #050607; }
.video-watermark { position: absolute; top: 13px; right: 13px; padding: 4px 7px; border: 1px solid rgba(255,255,255,.16); border-radius: 6px; color: rgba(255,255,255,.72); background: rgba(0,0,0,.28); pointer-events: none; font-size: 12px; font-weight: 700; }
.video-locked { display: grid; max-width: 360px; place-items: center; padding: 28px; color: #fff; text-align: center; }
.video-locked .ui-icon { width: 28px; height: 28px; }
.video-locked strong { margin-top: 11px; font-size: 18px; }
.video-locked p { margin: 7px 0 18px; color: #aeb4bd; font-size: 13px; line-height: 1.7; }
.watch-info-card { margin-top: 14px; padding: 22px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.watch-title-row { display: flex; align-items: start; justify-content: space-between; gap: 20px; }
.watch-lesson-label { color: var(--brand); font-size: 11px; font-weight: 700; }
.watch-title-row h1 { margin: 5px 0 0; font-size: 20px; font-weight: 710; line-height: 1.45; }
.watch-favorite { min-height: 36px; flex: 0 0 auto; padding: 0 12px; font-size: 12px; }
.watch-favorite .ui-icon { width: 15px; height: 15px; }
.watch-info-card > p { margin: 7px 0 0; color: var(--text-muted); font-size: 12px; }
.watch-progress { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 12px; margin-top: 18px; }
.watch-progress > div { height: 5px; overflow: hidden; border-radius: 4px; background: var(--surface-subtle); }
.watch-progress > div span { display: block; height: 100%; border-radius: inherit; background: var(--brand); transition: width var(--motion); }
.watch-progress small { color: var(--text-muted); font-size: 11px; }
.watch-progress b { color: var(--brand); font-variant-numeric: tabular-nums; }
.watch-note { margin-top: 18px; padding: 15px; border-left: 3px solid #f0a18d; border-radius: 0 var(--radius-sm) var(--radius-sm) 0; background: var(--surface-warm); }
.watch-note strong { font-size: 13px; }
.watch-note p { margin: 5px 0 0; color: #756963; font-size: 12px; line-height: 1.8; }
.watch-playlist { position: sticky; top: 86px; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.playlist-head { display: flex; align-items: end; justify-content: space-between; padding: 18px; border-bottom: 1px solid var(--border); }
.playlist-head .eyebrow { margin-bottom: 3px; }
.playlist-head h2 { margin: 0; font-size: 17px; font-weight: 700; }
.playlist-head > span { color: var(--text-muted); font-size: 11px; font-variant-numeric: tabular-nums; }
.playlist-items { max-height: 600px; overflow: auto; padding: 6px; }
.playlist-item { display: grid; grid-template-columns: 30px 1fr auto; align-items: center; gap: 9px; min-height: 54px; padding: 9px; border-radius: 7px; color: var(--text-secondary); }
.playlist-item:hover { background: var(--surface-subtle); }
.playlist-item.active { color: var(--brand); background: var(--brand-soft); }
.playlist-item > span { display: grid; width: 27px; height: 27px; place-items: center; border-radius: 6px; background: var(--surface-subtle); font-size: 12px; font-variant-numeric: tabular-nums; }
.playlist-item.active > span { color: #fff; background: var(--brand); }
.playlist-item strong { display: -webkit-box; overflow: hidden; font-size: 12px; font-weight: 600; line-height: 1.45; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
.playlist-item small { display: block; margin-top: 2px; color: var(--text-muted); font-size: 12px; }
.playlist-item i { color: var(--success); font-style: normal; font-size: 11px; }
.playlist-item i .ui-icon { width: 14px; height: 14px; }
.playlist-more { margin: 0; padding: 11px; border-top: 1px solid var(--border); color: var(--text-muted); text-align: center; font-size: 12px; }
.watch-mobile-actions { display: none; }

.empty-state { padding: 64px 20px; color: var(--text-secondary); text-align: center; font-size: 13px; }
.empty-state strong { display: block; margin-bottom: 6px; color: var(--text-primary); font-size: 15px; }
.course-grid > .empty-state { grid-column: 1 / -1; }
.footer { padding: 34px 0; border-top: 1px solid var(--border); color: var(--text-muted); background: var(--surface); font-size: 11px; }
.footer-inner { display: flex; justify-content: space-between; gap: 24px; }
.footer-brand { color: var(--text-secondary); font-weight: 650; }

.modal-backdrop { position: fixed; inset: 0; z-index: 100; display: grid; place-items: start center; padding: 88px 20px 30px; background: rgba(25, 29, 36, .52); backdrop-filter: blur(5px); }
.search-panel { width: min(100%, 660px); padding: 24px; border: 1px solid rgba(255,255,255,.5); border-radius: var(--radius-lg); background: var(--surface); box-shadow: var(--shadow-md); }
.search-head { display: flex; align-items: center; justify-content: space-between; }
.search-head h2 { margin: 0; font-size: 22px; font-weight: 720; }
.search-head .eyebrow { margin-bottom: 5px; }
.search-head .icon-button { color: var(--text-muted); font-size: 25px; }
.search-input-wrap { display: grid; grid-template-columns: 20px 1fr auto; align-items: center; gap: 10px; height: 50px; margin-top: 20px; padding: 0 13px; border: 1px solid var(--border-strong); border-radius: var(--radius-sm); color: var(--text-muted); }
.search-input-wrap:focus-within { border-color: var(--brand); box-shadow: 0 0 0 3px var(--focus-ring); }
.search-input-wrap input { min-width: 0; border: 0; outline: 0; color: var(--text-primary); background: transparent; font-size: 16px; }
.search-input-wrap input::placeholder { color: var(--text-muted); }
.search-input-wrap kbd { padding: 3px 6px; border: 1px solid var(--border); border-radius: 5px; color: var(--text-muted); background: var(--surface-subtle); font-size: 11px; }
.search-results { display: grid; max-height: 390px; gap: 4px; overflow: auto; margin-top: 12px; }
.search-result { display: grid; grid-template-columns: 40px 1fr auto; align-items: center; gap: 11px; padding: 10px; border-radius: var(--radius-sm); }
.search-result:hover { background: var(--surface-warm); }
.search-result:focus-visible { outline-offset: -2px; background: var(--surface-warm); }
.search-result-icon { display: grid; width: 40px; height: 40px; place-items: center; border-radius: 8px; color: var(--brand-ink); background: var(--brand-soft); font-size: 11px; font-weight: 700; }
.search-result strong { display: block; font-size: 13px; font-weight: 650; }
.search-result small { color: var(--text-muted); font-size: 11px; }
.search-result > span:last-child { color: var(--text-muted); font-size: 11px; }
.toast { position: fixed; right: 22px; bottom: 24px; z-index: 120; max-width: min(360px, calc(100vw - 32px)); padding: 12px 16px; border-radius: var(--radius-sm); color: #fff; background: #292d34; box-shadow: var(--shadow-md); opacity: 0; pointer-events: none; transform: translateY(10px); transition: opacity var(--motion), transform var(--motion); font-size: 13px; }
.toast.show { opacity: 1; transform: translateY(0); }
.mobile-nav { display: none; }

.small-button { min-height: 38px; padding-inline: 15px; font-size: 13px; }
.status-pill { display: inline-flex; width: max-content; align-items: center; gap: 6px; padding: 4px 8px; border-radius: 6px; font-size: 11px; font-weight: 700; line-height: 1.35; }
.status-pill.live { color: #c3341f; background: #ffebe7; }
.status-pill.upcoming { color: var(--warning); background: #fff3dc; }
.status-pill.replay { color: var(--success); background: #e9f6f1; }
.status-pill i, .live-dot { width: 7px; height: 7px; border-radius: 50%; background: currentColor; box-shadow: 0 0 0 3px rgba(217,60,48,.12); }

.live-home-section { padding: 0 0 64px; background: var(--surface); }
.live-home-card { display: grid; min-height: 70px; grid-template-columns: auto 1fr auto auto; align-items: center; gap: 16px; padding: 14px 18px; border-radius: var(--radius-md); color: #fff; background: #292d35; transition: background var(--motion), transform var(--motion); }
.live-home-card:hover { background: #20242b; transform: translateY(-1px); }
.live-home-card .live-dot { color: #ff6b52; background: #ff6b52; }
.live-home-card > span:nth-child(2) { display: grid; gap: 2px; }
.live-home-card strong { font-size: 13px; }
.live-home-card small { color: #d7dbe1; font-size: 12px; }
.live-home-meta { color: #b9c0c9; font-size: 12px; }
.live-home-card b { font-size: 12px; }

.live-feature { display: grid; overflow: hidden; grid-template-columns: 1.05fr .95fr; border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface); }
.live-feature-copy { padding: 38px; }
.live-feature-copy > .eyebrow { margin-top: 20px; }
.live-feature-copy h2 { max-width: 560px; margin: 0; font-size: 30px; font-weight: 740; line-height: 1.35; letter-spacing: -.035em; }
.live-feature-copy > p:not(.eyebrow) { max-width: 620px; margin: 14px 0 0; color: var(--text-secondary); font-size: 14px; line-height: 1.8; }
.live-feature-meta { display: flex; flex-wrap: wrap; gap: 16px; margin-top: 20px; color: var(--text-muted); font-size: 12px; }
.live-feature-meta span, .live-session-meta span { display: inline-flex; align-items: center; gap: 5px; }
.live-feature-meta .ui-icon, .live-session-meta .ui-icon { width: 15px; height: 15px; }
.live-feature-stage { position: relative; display: grid; min-height: 340px; place-items: center; align-content: center; gap: 25px; color: #fff; background: #20242b; }
.feature-teacher { display: grid; place-items: center; }
.feature-teacher > span { display: grid; width: 96px; height: 96px; place-items: center; border: 3px solid rgba(255,255,255,.14); border-radius: 50%; color: #fff; background: var(--brand); font-size: 32px; font-weight: 750; }
.feature-teacher strong { margin-top: 10px; font-size: 16px; }
.feature-teacher small { color: #aeb5c0; font-size: 11px; }
.feature-guests { display: flex; align-items: center; }
.feature-guests span, .feature-guests i { display: grid; width: 42px; height: 42px; margin-left: -5px; place-items: center; border: 2px solid #20242b; border-radius: 50%; background: #545d6a; font-style: normal; font-size: 12px; font-weight: 700; }
.feature-guests span:first-child { margin-left: 0; background: #6b62c8; }
.feature-guests span:nth-child(2) { background: #27876f; }
.feature-guests span:nth-child(3) { background: #a65b70; }
.feature-guests i { color: #d8dce2; background: #343a44; }
.live-feature-stage > p { position: absolute; right: 18px; bottom: 14px; margin: 0; color: #aeb5c0; font-size: 12px; }
.live-feature-stage > p b { display: inline-block; width: 6px; height: 6px; margin-right: 4px; border-radius: 50%; background: #36c88a; }
.live-list-head { margin-top: 54px; }
.live-session-list { display: grid; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.live-session-row { display: grid; grid-template-columns: 88px minmax(260px, 1fr) 250px auto; align-items: center; gap: 20px; min-height: 112px; padding: 18px 20px; border-bottom: 1px solid var(--border); }
.live-session-row:last-child { border-bottom: 0; }
.live-date { display: grid; align-content: center; padding-right: 18px; border-right: 1px solid var(--border); }
.live-date strong { font-size: 16px; font-weight: 700; }
.live-date span { color: var(--text-muted); font-size: 11px; }
.live-session-copy h3 { margin: 7px 0 0; font-size: 16px; font-weight: 680; line-height: 1.5; }
.live-session-copy p { margin: 3px 0 0; color: var(--text-muted); font-size: 11px; }
.live-session-meta { display: grid; gap: 6px; color: var(--text-secondary); font-size: 11px; }
.live-session-actions { display: grid; justify-items: end; gap: 7px; }
.live-session-actions > .small-button { min-width: 92px; }
.live-admin-actions { display: flex; align-items: center; gap: 10px; }
.live-admin-actions a, .live-admin-actions button { padding: 0; border: 0; color: var(--text-muted); background: transparent; font: inherit; font-size: 11px; cursor: pointer; }
.live-admin-actions a:hover { color: var(--brand); }
.live-admin-actions button:hover { color: var(--danger); }
.live-empty-state { display: grid; min-height: 300px; place-items: center; align-content: center; gap: 10px; padding: 40px 20px; border: 1px dashed var(--border-strong); border-radius: var(--radius-md); text-align: center; background: var(--surface); }
.live-empty-state > span { display: grid; width: 48px; height: 48px; place-items: center; border-radius: 12px; color: var(--brand); background: var(--brand-soft); font-weight: 750; }
.live-empty-state h2, .live-empty-state p { margin: 0; }
.live-empty-state h2 { font-size: 20px; }
.live-empty-state p { color: var(--text-muted); font-size: 12px; }
.live-workflow { display: grid; overflow: hidden; grid-template-columns: repeat(4,1fr); margin-top: 32px; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.live-workflow div { display: grid; min-height: 126px; align-content: center; gap: 4px; padding: 20px; border-right: 1px solid var(--border); }
.live-workflow div:last-child { border-right: 0; }
.live-workflow span { color: var(--brand); font-size: 11px; font-weight: 750; }
.live-workflow strong { font-size: 14px; }
.live-workflow small { color: var(--text-muted); font-size: 11px; }

.live-room-page { min-height: calc(100vh - var(--header-height)); padding: 24px 0 48px; color: #fff; background: #171a20; }
.room-heading { display: flex; align-items: flex-end; justify-content: space-between; gap: 24px; }
.room-heading a { color: #aeb5c0; font-size: 12px; }
.room-heading a:hover { color: #fff; }
.room-heading h1 { margin: 10px 0 0; font-size: 22px; font-weight: 680; line-height: 1.4; }
.room-heading p { margin: 4px 0 0; color: #929aa7; font-size: 11px; }
.room-heading-meta { display: flex; align-items: center; gap: 12px; color: #aeb5c0; font-size: 11px; }
.room-layout { display: grid; grid-template-columns: minmax(0,1fr) 318px; align-items: start; gap: 16px; margin-top: 20px; }
.room-main { min-width: 0; }
.room-stage { overflow: hidden; border: 1px solid #303640; border-radius: var(--radius-md); background: #0e1014; }
.teacher-stage { position: relative; display: grid; min-height: 420px; place-items: center; align-content: center; background: radial-gradient(circle at 50% 40%, #303541 0, #16191f 58%, #101217 100%); }
.stage-avatar { display: grid; width: 118px; height: 118px; place-items: center; border: 4px solid rgba(255,255,255,.1); border-radius: 50%; background: var(--brand); font-size: 38px; font-weight: 760; }
.stage-name { display: grid; margin-top: 14px; place-items: center; gap: 3px; }
.stage-name strong { font-size: 17px; }
.stage-name small { color: #aeb5c0; font-size: 11px; }
.stage-name i { display: inline-block; width: 6px; height: 6px; margin-right: 5px; border-radius: 50%; background: #36c88a; }
.stage-quality { position: absolute; top: 14px; right: 14px; padding: 4px 7px; border-radius: 5px; color: #b5bdc8; background: rgba(0,0,0,.3); font-size: 11px; }
.live-presentation { display: grid; min-height: 420px; place-items: center; padding: 30px; color: var(--text-primary); background: #f4f5f7; }
.presentation-empty { display: grid; max-width: 420px; place-items: center; gap: 8px; text-align: center; }
.presentation-empty > span, .presentation-file-icon { display: grid; width: 62px; height: 72px; place-items: center; border-radius: 8px; color: #fff; background: #e85b3f; font-size: 13px; font-weight: 800; box-shadow: 0 8px 18px rgba(232,91,63,.18); }
.presentation-empty strong { margin-top: 8px; font-size: 18px; }
.presentation-empty p { margin: 0; color: var(--text-muted); font-size: 12px; line-height: 1.7; }
.presentation-upload { display: inline-grid; min-height: 38px; margin-top: 8px; padding: 0 16px; place-items: center; border-radius: 7px; color: #fff; background: var(--brand); cursor: pointer; font-size: 12px; font-weight: 650; }
.presentation-upload:hover { background: var(--brand-hover); }
.presentation-ready { width: min(100%, 560px); grid-template-columns: 62px 1fr auto; align-items: center; gap: 16px; padding: 22px; border: 1px solid var(--border); border-radius: 12px; background: #fff; box-shadow: var(--shadow-sm); }
.presentation-ready:not([hidden]) { display: grid; }
.presentation-ready > div { display: grid; gap: 4px; min-width: 0; }
.presentation-ready strong { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 15px; }
.presentation-ready small { color: var(--text-muted); font-size: 11px; }
.presentation-sync { padding: 5px 8px; border-radius: 6px; color: var(--success); background: #e9f6f1; font-size: 11px; font-weight: 650; }
.live-whiteboard { position: relative; height: 420px; overflow: hidden; color: #24272e; background-color: #fbfbfa; background-image: radial-gradient(#d9dce0 1px, transparent 1px); background-size: 20px 20px; }
.whiteboard-topbar { position: absolute; top: 12px; right: 12px; left: 12px; z-index: 3; display: flex; align-items: center; justify-content: space-between; pointer-events: none; }
.whiteboard-topbar > button { display: grid; width: 36px; height: 36px; place-items: center; border: 1px solid #e0e2e5; border-radius: 9px; color: #5d636c; background: rgba(255,255,255,.94); box-shadow: 0 3px 12px rgba(31,35,42,.08); pointer-events: auto; cursor: pointer; font-size: 14px; }
.whiteboard-topbar > span { position: absolute; left: 46px; display: flex; align-items: center; gap: 7px; height: 36px; padding: 0 11px 0 7px; border: 1px solid #e0e2e5; border-radius: 9px; background: rgba(255,255,255,.94); box-shadow: 0 3px 12px rgba(31,35,42,.08); }
.whiteboard-topbar > span i { display: grid; width: 23px; height: 23px; place-items: center; border-radius: 6px; color: #fff; background: #24272e; font-style: normal; font-size: 10px; font-weight: 750; }
.whiteboard-topbar strong { font-size: 11px; }
.whiteboard-topbar > b { display: inline-flex; height: 32px; align-items: center; gap: 6px; padding: 0 10px; border: 1px solid #dce9e4; border-radius: 8px; color: #16775d; background: rgba(245,252,249,.94); font-size: 10px; font-weight: 650; }
.whiteboard-topbar > b i { width: 6px; height: 6px; border-radius: 50%; background: #2aaf81; }
.whiteboard-toolbar { position: absolute; bottom: 12px; left: 50%; z-index: 3; display: flex; min-height: 46px; align-items: center; gap: 5px; padding: 5px; border: 1px solid #dedfe2; border-radius: 12px; background: rgba(255,255,255,.96); box-shadow: 0 7px 22px rgba(31,35,42,.14); transform: translateX(-50%); }
.whiteboard-toolbar button { display: grid; min-width: 34px; height: 34px; padding: 0 8px; place-items: center; border: 0; border-radius: 8px; color: #555b65; background: transparent; cursor: pointer; font-size: 15px; }
.whiteboard-toolbar button:hover, .whiteboard-toolbar button.active { color: #16181d; background: #eef0f2; }
.whiteboard-toolbar button[data-board-color] { min-width: 21px; width: 21px; height: 21px; padding: 0; border: 3px solid #fff; border-radius: 50%; background: var(--board-color); box-shadow: 0 0 0 1px #c9cdd2; }
.whiteboard-toolbar button[data-board-color].active { box-shadow: 0 0 0 2px #24272e; }
.whiteboard-toolbar .toolbar-divider { width: 1px; height: 24px; margin: 0 2px; background: #e0e2e5; }
.whiteboard-zoom { position: absolute; bottom: 12px; left: 12px; z-index: 3; display: flex; height: 34px; align-items: center; overflow: hidden; border: 1px solid #dedfe2; border-radius: 9px; background: rgba(255,255,255,.96); box-shadow: 0 4px 14px rgba(31,35,42,.1); }
.whiteboard-zoom button { width: 32px; height: 100%; border: 0; color: #555b65; background: transparent; cursor: pointer; font-size: 15px; }
.whiteboard-zoom button:hover { background: #eef0f2; }
.whiteboard-zoom span { min-width: 42px; text-align: center; font-size: 10px; font-variant-numeric: tabular-nums; }
#liveWhiteboard { display: block; width: 100%; height: 100%; cursor: crosshair; touch-action: none; background: transparent; }
#liveWhiteboard[data-board-cursor="select"] { cursor: default; }
#liveWhiteboard[data-board-cursor="eraser"] { cursor: cell; }
.guest-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 1px; background: #303640; }
.guest-tile { display: grid; min-width: 0; min-height: 118px; place-items: center; align-content: center; gap: 3px; background: #1e2229; }
.guest-tile > span { display: grid; width: 38px; height: 38px; place-items: center; border-radius: 50%; background: #586170; font-size: 12px; font-weight: 700; }
.guest-tile.speaking { box-shadow: inset 0 0 0 2px #39bf87; }
.guest-tile.speaking > span { background: #2a8f70; }
.guest-tile strong { overflow: hidden; max-width: 90%; text-overflow: ellipsis; white-space: nowrap; font-size: 11px; }
.guest-tile small { display: inline-flex; align-items: center; gap: 3px; color: #8e97a4; font-size: 11px; }
.guest-tile small .ui-icon { width: 12px; height: 12px; }
.guest-tile.empty { color: #7f8895; background: #191c22; }
.guest-tile.empty > span { border: 1px dashed #4b535e; background: transparent; font-size: 18px; font-weight: 400; }
.room-controls { display: flex; min-height: 68px; align-items: center; justify-content: center; gap: 8px; margin-top: 10px; padding: 8px 12px; border: 1px solid #303640; border-radius: var(--radius-md); background: #20242b; }
.room-control { display: inline-grid; min-width: 72px; min-height: 48px; place-items: center; align-content: center; gap: 3px; border: 0; border-radius: 7px; color: #d7dbe1; background: transparent; cursor: pointer; font-size: 11px; }
.room-control:hover { background: #2c313a; }
.room-control .ui-icon { width: 19px; height: 19px; }
.room-control.off { color: #ff8b78; background: #3a2929; }
.room-control.raise-hand { color: #ff9a80; }
.room-control.requested { color: #fff; background: var(--brand); }
.room-leave { display: inline-grid; min-height: 38px; margin-left: 8px; padding: 0 16px; place-items: center; border-radius: 7px; color: #ff9d90; background: #3a2929; font-size: 11px; }
.room-replay-note { display: flex; align-items: center; gap: 10px; margin-top: 10px; padding: 12px 14px; border: 1px solid #303640; border-radius: var(--radius-sm); color: #aeb5c0; background: #20242b; }
.room-replay-note > .ui-icon { width: 20px; height: 20px; color: #ff8b72; }
.room-replay-note span { display: grid; }
.room-replay-note strong { color: #e8ebef; font-size: 11px; }
.room-replay-note small { font-size: 12px; }
.room-side { position: sticky; top: 86px; overflow: hidden; border: 1px solid #303640; border-radius: var(--radius-md); background: #20242b; }
.room-side-tabs { display: grid; height: 50px; grid-template-columns: 1fr 1fr; border-bottom: 1px solid #303640; }
.room-side-tabs button { position: relative; border: 0; color: #929aa7; background: transparent; cursor: pointer; font-size: 11px; }
.room-side-tabs button.active { color: #fff; font-weight: 650; }
.room-side-tabs button.active::after { content: ""; position: absolute; right: 28px; bottom: -1px; left: 28px; height: 2px; background: var(--brand); }
.room-side-tabs span { display: inline-grid; width: 17px; height: 17px; margin-left: 3px; place-items: center; border-radius: 50%; color: #fff; background: var(--brand); font-size: 12px; }
.chat-messages { display: grid; max-height: 560px; min-height: 430px; align-content: start; gap: 18px; overflow-y: auto; padding: 18px; }
.chat-messages > div { display: grid; grid-template-columns: 30px 1fr; align-items: start; gap: 9px; }
.chat-avatar { display: grid; width: 30px; height: 30px; place-items: center; border-radius: 50%; background: #505966; font-size: 12px; font-weight: 700; }
.chat-avatar.teacher { background: var(--brand); }
.chat-avatar.me { background: #277e67; }
.chat-messages p { display: grid; gap: 3px; margin: 0; }
.chat-messages strong { color: #dfe3e8; font-size: 12px; font-weight: 650; }
.chat-messages small { color: #aeb5c0; font-size: 11px; line-height: 1.65; }
.chat-form { display: grid; grid-template-columns: 1fr auto; gap: 7px; padding: 12px; border-top: 1px solid #303640; }
.chat-form input { min-width: 0; height: 40px; padding: 0 11px; border: 1px solid #3a414c; border-radius: 7px; outline: 0; color: #fff; background: #171a20; font-size: 16px; }
.chat-form input:focus { border-color: #f47b62; box-shadow: 0 0 0 3px rgba(242,85,49,.16); }
.chat-form button { padding: 0 13px; border: 0; border-radius: 7px; color: #fff; background: var(--brand); cursor: pointer; font-size: 11px; }

.studio-section { padding-top: 34px; }
.studio-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.studio-toolbar > div { display: flex; align-items: center; gap: 10px; }
.studio-toolbar strong { font-size: 16px; }
.studio-stats { display: grid; grid-template-columns: repeat(4,1fr); margin-top: 20px; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); background: var(--surface); }
.studio-stats div { display: grid; min-height: 88px; align-content: center; padding: 16px 22px; border-right: 1px solid var(--border); }
.studio-stats div:last-child { border-right: 0; }
.studio-stats strong { font-size: 22px; font-weight: 730; font-variant-numeric: tabular-nums; }
.studio-stats span { color: var(--text-muted); font-size: 11px; }
.studio-layout { display: grid; grid-template-columns: 430px 1fr; align-items: start; gap: 18px; margin-top: 24px; }
.upload-panel, .media-panel { border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.upload-panel { padding: 22px; }
.media-panel { overflow: hidden; }
.panel-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; }
.panel-heading .eyebrow { margin-bottom: 4px; }
.panel-heading h2 { margin: 0; font-size: 20px; font-weight: 710; }
.upload-secure { display: inline-flex; align-items: center; gap: 5px; color: var(--success); font-size: 12px; }
.upload-secure .ui-icon { width: 14px; height: 14px; }
.upload-form { display: grid; gap: 15px; margin-top: 20px; }
.field { display: grid; gap: 6px; }
.field > span { color: var(--text-secondary); font-size: 11px; font-weight: 600; }
.field input, .field select { width: 100%; height: 44px; padding: 0 12px; border: 1px solid var(--border-strong); border-radius: var(--radius-sm); outline: 0; color: var(--text-primary); background: var(--surface); font-size: 16px; }
.field input:focus, .field select:focus { border-color: var(--brand); box-shadow: 0 0 0 3px var(--focus-ring); }
.upload-drop { display: grid; min-height: 148px; place-items: center; align-content: center; gap: 5px; padding: 18px; border: 1px dashed #d8a89b; border-radius: var(--radius-sm); color: var(--text-secondary); background: var(--surface-warm); text-align: center; cursor: pointer; transition: border-color var(--motion), background var(--motion); }
.upload-drop:hover, .upload-drop.dragging { border-color: var(--brand); background: var(--brand-soft); }
.upload-drop .ui-icon { width: 25px; height: 25px; color: var(--brand); }
.upload-drop strong { margin-top: 5px; color: var(--text-primary); font-size: 13px; }
.upload-drop small { color: var(--text-muted); font-size: 12px; }
.upload-selection { grid-template-columns: 40px 1fr auto; align-items: center; gap: 10px; padding: 10px; border: 1px solid var(--border); border-radius: var(--radius-sm); }
.upload-selection:not([hidden]) { display: grid; }
.upload-selection > span:nth-child(2) { display: grid; min-width: 0; }
.upload-selection strong { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 11px; }
.upload-selection small { color: var(--text-muted); font-size: 12px; }
.upload-progress > div { height: 6px; overflow: hidden; border-radius: 4px; background: var(--surface-subtle); }
.upload-progress > div span { display: block; width: 0; height: 100%; border-radius: inherit; background: var(--brand); transition: width 140ms linear; }
.upload-progress p { display: flex; margin: 6px 0 0; justify-content: space-between; color: var(--text-muted); font-size: 12px; }
.upload-progress strong { color: var(--text-secondary); font-weight: 600; }
.transcode-options { display: grid; gap: 7px; color: var(--text-secondary); font-size: 11px; }
.transcode-options label { display: flex; align-items: center; gap: 7px; }
.transcode-options input { accent-color: var(--brand); }
.upload-submit { width: 100%; }
.form-help { margin: -4px 0 0; color: var(--text-muted); font-size: 12px; line-height: 1.6; }
.media-panel > .panel-heading { padding: 22px 22px 16px; border-bottom: 1px solid var(--border); }
.media-list { display: grid; }
.media-row { display: grid; min-width: 0; grid-template-columns: 44px minmax(0,1fr) 76px auto; align-items: center; gap: 12px; min-height: 76px; padding: 12px 18px; border-bottom: 1px solid var(--border); }
.media-kind { display: grid; width: 40px; height: 40px; place-items: center; border-radius: 7px; color: var(--brand-ink); background: var(--brand-soft); font-size: 11px; font-weight: 750; }
.media-copy { display: grid; min-width: 0; }
.media-copy strong { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 12px; }
.media-copy small { overflow: hidden; color: var(--text-muted); text-overflow: ellipsis; white-space: nowrap; font-size: 12px; }
.media-status { display: inline-flex; align-items: center; gap: 5px; font-size: 12px; font-weight: 650; }
.media-status i { width: 6px; height: 6px; border-radius: 50%; background: currentColor; }
.media-status.ready { color: var(--success); }
.media-status.processing { color: var(--brand); }
.media-status.waiting { color: var(--warning); }
.storage-tip { display: grid; grid-template-columns: 34px 1fr auto; align-items: center; gap: 10px; margin: 16px; padding: 13px; border-radius: var(--radius-sm); background: var(--surface-subtle); }
.storage-tip > span { display: grid; width: 34px; height: 34px; place-items: center; border-radius: 7px; color: var(--brand); background: var(--surface); }
.storage-tip > span .ui-icon { width: 17px; height: 17px; }
.storage-tip p { display: grid; margin: 0; }
.storage-tip strong { font-size: 11px; }
.storage-tip small { color: var(--text-muted); font-size: 12px; }
.storage-tip b { color: var(--text-secondary); font-size: 12px; font-variant-numeric: tabular-nums; }

.studio-course-section { margin-top: 58px; }
.studio-course-section .section-head { align-items: center; }
.admin-course-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 18px; }
.admin-course-card { overflow: hidden; min-width: 0; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); transition: border-color var(--motion), transform var(--motion); }
.admin-course-card:hover { border-color: #e7a794; transform: translateY(-2px); }
.admin-course-cover { position: relative; display: flex; height: 128px; align-items: flex-end; overflow: hidden; padding: 14px; color: #fff; background: var(--course-gradient); }
.admin-course-cover > span { position: absolute; top: 13px; right: 16px; font-size: 34px; font-weight: 800; opacity: .17; }
.admin-course-cover > i { position: relative; padding: 4px 8px; border-radius: 5px; background: rgba(20,22,26,.45); font-style: normal; font-size: 12px; font-weight: 650; }
.admin-course-body { padding: 15px; }
.admin-course-body > div { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.admin-course-body > div small { overflow: hidden; color: var(--text-muted); text-overflow: ellipsis; white-space: nowrap; font-size: 12px; }
.admin-course-body h3 { display: -webkit-box; min-height: 45px; margin: 11px 0 0; overflow: hidden; font-size: 15px; font-weight: 680; line-height: 1.5; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
.admin-course-body > p { display: -webkit-box; min-height: 40px; margin: 6px 0 0; overflow: hidden; color: var(--text-secondary); font-size: 11px; line-height: 1.7; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
.admin-course-body footer { display: flex; margin-top: 13px; padding-top: 12px; align-items: center; justify-content: space-between; border-top: 1px solid var(--border); }
.admin-course-body footer span { color: var(--text-muted); font-size: 12px; }
.admin-course-body footer strong { color: var(--brand); font-size: 14px; }
.studio-tool-section { margin-top: 58px; }
.admin-tool-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 16px; }
.admin-tool-card { display: grid; min-width: 0; grid-template-columns: 64px 1fr auto; align-items: center; gap: 16px; padding: 18px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); transition: border-color var(--motion), transform var(--motion); }
.admin-tool-card:hover { border-color: #e7a794; transform: translateY(-2px); }
.admin-tool-icon { display: grid; width: 64px; height: 64px; place-items: center; border-radius: 14px; color: #fff; background: var(--tool-gradient); font-size: 13px; font-weight: 800; }
.admin-tool-card > span:nth-child(2) { min-width: 0; }
.admin-tool-card small { color: var(--text-muted); font-size: 11px; }
.admin-tool-card strong { display: block; margin-top: 3px; font-size: 15px; }
.admin-tool-card p { display: -webkit-box; margin: 5px 0 0; overflow: hidden; color: var(--text-secondary); font-size: 12px; line-height: 1.6; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
.admin-tool-card b { color: var(--brand); font-size: 11px; white-space: nowrap; }
.tool-live-preview { pointer-events: none; }

.account-menu { position: relative; }
.account-trigger { display: flex; min-height: 44px; align-items: center; gap: 8px; padding: 4px 8px 4px 5px; border: 1px solid transparent; border-radius: 10px; background: transparent; cursor: pointer; transition: border-color var(--motion), background var(--motion); }
.account-trigger:hover, .account-trigger[aria-expanded="true"] { border-color: var(--border); background: var(--surface-subtle); }
.account-avatar, .profile-avatar { display: grid; place-items: center; flex: 0 0 auto; color: #fff; background: linear-gradient(135deg,#ff7658,#e84327); font-weight: 750; }
.account-avatar { width: 34px; height: 34px; border-radius: 9px; font-size: 12px; }
.account-trigger-copy { display: grid; min-width: 52px; text-align: left; line-height: 1.3; }
.account-trigger-copy strong { font-size: 11px; }
.account-trigger-copy small { color: var(--text-muted); font-size: 11px; }
.account-trigger > svg { width: 15px; height: 15px; fill: none; stroke: var(--text-muted); stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.8; }
.account-dropdown { position: absolute; top: calc(100% + 10px); right: 0; z-index: 80; width: 230px; padding: 8px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); box-shadow: var(--shadow-md); }
.account-menu-head { display: flex; align-items: center; gap: 10px; margin-bottom: 6px; padding: 10px; border-bottom: 1px solid var(--border); }
.account-menu-head > span:last-child { display: grid; line-height: 1.45; }
.account-menu-head strong { font-size: 12px; }
.account-menu-head small { color: var(--text-muted); font-size: 11px; }
.account-dropdown > a, .account-dropdown > button { display: flex; width: 100%; min-height: 40px; align-items: center; justify-content: space-between; padding: 0 10px; border: 0; border-radius: 7px; background: transparent; cursor: pointer; color: var(--text-secondary); text-align: left; font-size: 12px; }
.account-dropdown > a:hover, .account-dropdown > button:hover { color: var(--text-primary); background: var(--surface-warm); }
.account-dropdown > button { margin-top: 4px; border-top: 1px solid var(--border); border-radius: 0 0 7px 7px; color: var(--text-muted); }

.account-page { padding-top: 34px; }
.account-layout { display: grid; grid-template-columns: 220px minmax(0,1fr); align-items: start; gap: 22px; }
.account-sidebar { position: sticky; top: calc(var(--header-height) + 22px); overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.account-profile-card { display: grid; justify-items: center; padding: 24px 16px 18px; border-bottom: 1px solid var(--border); }
.profile-avatar { width: 56px; height: 56px; margin-bottom: 10px; border-radius: 16px; font-size: 18px; }
.account-profile-card strong { font-size: 15px; }
.account-profile-card small { margin-top: 2px; color: var(--text-muted); font-size: 12px; }
.account-sidebar nav { display: grid; padding: 8px; }
.account-sidebar nav a { display: flex; min-height: 42px; align-items: center; justify-content: space-between; padding: 0 11px; border-radius: 7px; color: var(--text-secondary); font-size: 12px; }
.account-sidebar nav a:hover { background: var(--surface-subtle); }
.account-sidebar nav a.active { color: var(--brand-ink); background: var(--brand-soft); font-weight: 700; }
.account-main { display: grid; min-width: 0; gap: 18px; }
.account-welcome { display: flex; min-height: 150px; align-items: center; justify-content: space-between; gap: 24px; padding: 28px 30px; border-radius: var(--radius-md); color: #fff; background: linear-gradient(120deg,#282c34 0%,#393e48 72%,#4e403b 100%); }
.account-welcome h2 { margin: 11px 0 3px; font-size: 23px; }
.account-welcome p { margin: 0; color: #c9ced6; font-size: 12px; }
.account-quick-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 12px; }
.account-quick-grid a { display: grid; min-width: 0; padding: 18px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); transition: border-color var(--motion), transform var(--motion); }
.account-quick-grid a:hover { border-color: #e7a794; transform: translateY(-2px); }
.account-quick-grid strong { color: var(--brand); font-size: 24px; line-height: 1.2; }
.account-quick-grid span { margin-top: 8px; font-size: 13px; font-weight: 700; }
.account-quick-grid small { margin-top: 2px; overflow: hidden; color: var(--text-muted); text-overflow: ellipsis; white-space: nowrap; font-size: 11px; }
.settings-panel { min-width: 0; padding: 24px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
#profileForm .editor-fields { max-width: 640px; }
.settings-panel-head { display: flex; align-items: center; justify-content: space-between; gap: 18px; margin-bottom: 22px; padding-bottom: 16px; border-bottom: 1px solid var(--border); }
.settings-panel-head h2 { margin: 0; font-size: 18px; }
.settings-panel-head p { margin: 2px 0 0; color: var(--text-muted); font-size: 12px; }
.settings-divider { height: 1px; margin: 22px 0; background: var(--border); }
.setting-switches { display: grid; gap: 2px; }
.setting-switches label { display: flex; min-height: 58px; align-items: center; justify-content: space-between; gap: 18px; padding: 8px 0; cursor: pointer; }
.setting-switches label > span { display: grid; }
.setting-switches strong { font-size: 12px; }
.setting-switches small { color: var(--text-muted); font-size: 12px; }
.setting-switches input { width: 38px; height: 21px; accent-color: var(--brand); }
.security-rows { display: grid; }
.security-rows > div { display: flex; min-height: 66px; align-items: center; justify-content: space-between; gap: 16px; border-bottom: 1px solid var(--border); }
.security-rows > div:last-child { border-bottom: 0; }
.security-rows span { display: grid; }
.security-rows strong { font-size: 12px; }
.security-rows small { color: var(--text-muted); font-size: 12px; }
.admin-setting-grid { display: grid; grid-template-columns: minmax(0,1.05fr) minmax(0,.95fr); gap: 18px; }
.role-list { display: grid; }
.role-list > div { display: grid; min-height: 66px; grid-template-columns: 38px minmax(0,1fr) auto; align-items: center; gap: 11px; border-bottom: 1px solid var(--border); }
.role-list > div:last-child { border-bottom: 0; }
.role-icon { display: grid; width: 36px; height: 36px; place-items: center; border-radius: 9px; font-size: 12px; font-weight: 750; }
.role-icon.owner { color: #73431c; background: #fff0df; }
.role-icon.teacher { color: #4c36a8; background: #eeeaff; }
.role-icon.service { color: #08745f; background: #e5f6f0; }
.role-list span:nth-child(2) { display: grid; }
.role-list strong { font-size: 11px; }
.role-list small { color: var(--text-muted); font-size: 11px; }
.role-list b { color: var(--text-secondary); font-size: 12px; }
.invitation-panel { padding-bottom: 12px; }
.invite-create-form { display: grid; grid-template-columns: 1.3fr 1.4fr .65fr .9fr .7fr auto; align-items: end; gap: 10px; padding: 16px; border-radius: var(--radius-sm); background: var(--surface-subtle); }
.invite-create-form .field { gap: 4px; }
.invite-create-form .field > span { font-size: 11px; }
.invite-create-form input, .invite-create-form select { height: 42px; background: var(--surface); font-size: 14px; }
.invite-create-form > button { min-height: 42px; white-space: nowrap; }
.invite-list-head { display: flex; align-items: center; justify-content: space-between; gap: 14px; margin-top: 24px; padding: 0 2px 10px; }
.invite-list-head strong { font-size: 13px; }
.invite-list-head span { color: var(--text-muted); font-size: 12px; }
.invite-list { display: grid; }
.invite-row { display: grid; min-width: 0; grid-template-columns: 1.35fr 1.25fr .72fr .88fr .7fr 1.45fr; align-items: center; gap: 10px; min-height: 76px; padding: 12px 2px; border-top: 1px solid var(--border); }
.invite-row > div:not(.invite-actions) { display: grid; min-width: 0; }
.invite-row span, .invite-row strong { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 12px; }
.invite-code strong { color: var(--text-primary); font-size: 12px; font-variant-numeric: tabular-nums; letter-spacing: .03em; }
.invite-row small { overflow: hidden; color: var(--text-muted); text-overflow: ellipsis; white-space: nowrap; font-size: 12px; }
.invite-status { display: inline-flex; width: max-content; align-items: center; gap: 5px; padding: 4px 7px; border-radius: 6px; font-size: 11px; font-weight: 700; }
.invite-status i { width: 6px; height: 6px; border-radius: 50%; background: currentColor; }
.invite-status.active { color: var(--success); background: #e9f6f1; }
.invite-status.disabled { color: var(--text-muted); background: var(--surface-subtle); }
.invite-status.expired { color: #7a4a10; background: #fff2df; }
.invite-actions { display: flex; justify-content: flex-end; gap: 5px; }
.invite-actions .text-button { padding: 4px; border: 0; background: transparent; color: var(--text-secondary); font-size: 11px; white-space: nowrap; }
.invite-actions .text-button:first-child { color: var(--brand); font-weight: 700; }
.settings-note { padding: 15px 18px; border-left: 3px solid var(--brand); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; background: var(--brand-soft); }
.settings-note strong { font-size: 11px; }
.settings-note p { margin: 3px 0 0; color: var(--text-secondary); font-size: 11px; }

.register-page { display: grid; min-height: calc(100vh - var(--header-height)); place-items: center; padding: 48px 20px 88px; background: linear-gradient(145deg,#fff 0%,#f7f8fa 55%,#fff2ed 100%); }
.register-card { width: min(100%, 520px); padding: 32px 36px; border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface); box-shadow: var(--shadow-md); }
.register-brand { display: inline-flex; align-items: center; gap: 9px; }
.register-brand img { width: 42px; height: 42px; object-fit: contain; }
.register-brand span { display: grid; line-height: 1.35; }
.register-brand strong { font-size: 13px; }
.register-brand small { color: var(--text-muted); font-size: 12px; }
.register-heading { margin-top: 26px; }
.register-heading h1 { margin: 10px 0 4px; font-size: 27px; }
.register-heading p { margin: 0; color: var(--text-secondary); font-size: 11px; }
.register-form { display: grid; gap: 15px; margin-top: 24px; }
.register-form > .primary-button { width: 100%; margin-top: 5px; }
.invite-validation { font-size: 11px !important; }
.invite-validation.valid { color: var(--success) !important; }
.invite-validation.invalid { color: var(--danger) !important; }
.agreement { display: flex; align-items: center; gap: 8px; color: var(--text-secondary); font-size: 12px; }
.agreement input { accent-color: var(--brand); }
.register-help { margin: 18px 0 0; color: var(--text-muted); text-align: center; font-size: 12px; }
.register-help a { color: var(--brand); font-weight: 650; }

.course-editor-page { min-height: calc(100vh - var(--header-height)); padding-bottom: 72px; background: var(--background); }
.editor-topbar { position: sticky; top: var(--header-height); z-index: 40; border-bottom: 1px solid var(--border); background: rgba(255,255,255,.97); backdrop-filter: blur(12px); }
.editor-topbar .container { display: flex; min-height: 66px; align-items: center; justify-content: space-between; gap: 20px; }
.editor-topbar .container > div { display: flex; align-items: center; gap: 10px; }
.editor-topbar a:not(.outline-button) { color: var(--text-secondary); font-size: 11px; }
.editor-topbar strong { font-size: 16px; }
.editor-layout { display: grid; grid-template-columns: minmax(0,1fr) 340px; align-items: start; gap: 20px; padding-top: 26px; }
.editor-main { display: grid; gap: 16px; }
.editor-aside { position: sticky; top: calc(var(--header-height) + 88px); display: grid; gap: 16px; }
.editor-panel { padding: 24px; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--surface); }
.editor-panel-head { margin-bottom: 22px; padding-bottom: 17px; border-bottom: 1px solid var(--border); }
.editor-panel-head > div { display: grid; grid-template-columns: 26px 1fr; align-items: center; column-gap: 9px; }
.editor-panel-head span { grid-row: 1 / span 2; display: grid; width: 26px; height: 26px; place-items: center; border-radius: 6px; color: var(--brand); background: var(--brand-soft); font-size: 11px; font-weight: 750; }
.editor-panel-head h2 { margin: 0; font-size: 18px; font-weight: 710; }
.editor-panel-head p { margin: 1px 0 0; color: var(--text-muted); font-size: 12px; }
.editor-fields { display: grid; gap: 16px; }
.editor-fields.two-columns { grid-template-columns: repeat(2,minmax(0,1fr)); }
.editor-fields .full { grid-column: 1 / -1; }
.field textarea { width: 100%; padding: 10px 12px; resize: vertical; border: 1px solid var(--border-strong); border-radius: var(--radius-sm); outline: 0; color: var(--text-primary); background: var(--surface); font: inherit; font-size: 16px; line-height: 1.7; }
.field textarea:focus { border-color: var(--brand); box-shadow: 0 0 0 3px var(--focus-ring); }
.field > span b { color: var(--danger); }
.field > small { color: var(--text-muted); font-size: 11px; line-height: 1.5; }
.cover-editor { display: grid; grid-template-columns: 280px 1fr; align-items: center; gap: 22px; }
.editor-cover-preview { position: relative; display: flex; height: 158px; align-items: flex-end; overflow: hidden; padding: 14px; border-radius: var(--radius-sm); color: #fff; background: var(--course-gradient); }
.editor-cover-preview strong { position: absolute; top: 14px; right: 17px; font-size: 36px; opacity: .2; }
.editor-cover-preview span { padding: 4px 8px; border-radius: 5px; background: rgba(20,22,26,.2); font-size: 11px; }
.cover-editor > div:last-child > p { margin: 10px 0 0; color: var(--text-muted); font-size: 12px; line-height: 1.6; }
.cover-colors { display: flex; margin-top: 15px; align-items: center; gap: 7px; }
.cover-colors span { margin-right: 3px; color: var(--text-secondary); font-size: 12px; }
.cover-colors i { width: 18px; height: 18px; border: 2px solid #fff; border-radius: 50%; background: var(--swatch); box-shadow: 0 0 0 1px var(--border); }
.pricing-editor { display: grid; gap: 20px; }
.access-options { display: grid; grid-template-columns: repeat(2,1fr); gap: 10px; }
.choice-card { display: flex; min-height: 78px; align-items: flex-start; gap: 10px; padding: 14px; border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; }
.choice-card.selected { border-color: #efaa98; background: var(--surface-warm); }
.choice-card input { margin-top: 3px; accent-color: var(--brand); }
.choice-card span { display: grid; }
.choice-card strong { font-size: 12px; }
.choice-card small { color: var(--text-muted); font-size: 12px; line-height: 1.5; }
.price-input { display: grid; grid-template-columns: 34px 1fr; border: 1px solid var(--border-strong); border-radius: var(--radius-sm); }
.price-input:focus-within { border-color: var(--brand); box-shadow: 0 0 0 3px var(--focus-ring); }
.price-input i { display: grid; place-items: center; border-right: 1px solid var(--border); color: var(--text-muted); background: var(--surface-subtle); font-style: normal; font-size: 12px; }
.price-input input { border: 0; box-shadow: none !important; }
.price-input:has(input:disabled) { opacity: .5; background: var(--surface-subtle); }
.permission-options { display: flex; flex-wrap: wrap; gap: 10px 20px; padding-top: 16px; border-top: 1px solid var(--border); color: var(--text-secondary); font-size: 11px; }
.permission-options label { display: flex; align-items: center; gap: 6px; }
.permission-options input { accent-color: var(--brand); }
.course-content-summary { display: grid; grid-template-columns: repeat(3,1fr) auto; align-items: center; gap: 14px; }
.course-content-summary > div { display: grid; min-height: 62px; align-content: center; padding: 0 14px; border-left: 1px solid var(--border); }
.course-content-summary strong { font-size: 18px; }
.course-content-summary span { color: var(--text-muted); font-size: 12px; }
.editor-panel-head-action { display: flex; align-items: center; justify-content: space-between; gap: 18px; }
.editor-panel-head-action > div { flex: 1; }
.editor-repeat-list { display: grid; gap: 8px; }
.editor-repeat-row { display: grid; align-items: end; gap: 9px; padding: 11px; border: 1px solid var(--border); border-radius: var(--radius-sm); background: var(--surface); }
.lesson-editor-row { grid-template-columns: 34px minmax(0,1fr) 140px 32px; }
.outcome-editor-row { grid-template-columns: 34px minmax(0,1fr) 32px; }
.resource-editor-row { grid-template-columns: 34px 82px minmax(170px,1fr) minmax(160px,1fr) 32px; }
.editor-item-number { display: grid; width: 30px; height: 34px; place-items: center; border-radius: 6px; color: var(--text-muted); background: var(--surface-subtle); font-size: 12px; font-variant-numeric: tabular-nums; }
.editor-repeat-row label { display: grid; min-width: 0; gap: 4px; }
.editor-repeat-row label > span { color: var(--text-muted); font-size: 11px; }
.editor-repeat-row input, .editor-repeat-row select { width: 100%; height: 34px; min-width: 0; padding: 0 9px; border: 1px solid var(--border-strong); border-radius: 6px; outline: 0; color: var(--text-primary); background: var(--surface); font: inherit; font-size: 14px; }
.editor-repeat-row input:focus, .editor-repeat-row select:focus { border-color: var(--brand); box-shadow: 0 0 0 3px var(--focus-ring); }
.editor-remove { display: grid; width: 32px; height: 34px; place-items: center; align-self: end; border: 1px solid transparent; border-radius: 6px; color: var(--text-muted); font-size: 20px; }
.editor-remove:hover { border-color: #f2c8be; color: var(--danger); background: #fff2ef; }
.editor-section-footer { display: flex; margin-top: 14px; align-items: center; justify-content: space-between; gap: 16px; color: var(--text-muted); font-size: 12px; }
.editor-section-footer b { color: var(--text-primary); font-size: 12px; }
.editor-empty { padding: 25px 16px; border: 1px dashed var(--border-strong); border-radius: var(--radius-sm); color: var(--text-muted); text-align: center; font-size: 11px; }
.preview-panel { padding: 18px; }
.preview-panel .panel-heading { margin-bottom: 14px; }
.preview-panel .panel-heading h2 { font-size: 16px; }
.editor-live-card { pointer-events: none; }
.editor-live-card:hover { border-color: var(--border); transform: none; }
.editor-live-card .course-cover { height: 132px; }
.editor-live-card .course-body { padding: 14px; }
.editor-live-card .course-title { min-height: auto; font-size: 14px; }
.editor-live-card .course-desc { min-height: 40px; font-size: 11px; }
.editor-live-card .course-meta { gap: 10px; font-size: 12px; }
.editor-live-card .course-footer { margin-top: 12px; padding-top: 11px; }
.danger-action { color: var(--danger); border-color: #efc9c4; }
.danger-action:hover { color: #a82020; border-color: #dc8f85; background: #fff5f3; }
.live-editor-preview > strong { display: block; margin-top: 18px; font-size: 17px; line-height: 1.5; }
.live-editor-preview > p { margin: 5px 0 16px; color: var(--text-muted); font-size: 11px; }
.live-editor-preview > div:last-child { display: grid; gap: 7px; padding-top: 14px; border-top: 1px solid var(--border); color: var(--text-secondary); font-size: 11px; }
.publish-panel h3 { margin: 0; font-size: 15px; }
.publish-panel ul { display: grid; gap: 9px; margin: 15px 0 18px; padding: 0; list-style: none; color: var(--text-secondary); font-size: 11px; }
.publish-panel li::before { content: "○"; display: inline-block; width: 20px; color: var(--text-muted); }
.publish-panel li.done::before { content: "✓"; color: var(--success); font-weight: 800; }
.publish-panel .outline-button { width: 100%; }
.publish-panel > p { margin: 11px 0 0; color: var(--text-muted); font-size: 11px; line-height: 1.6; }
.side-edit-link { display: inline-flex; margin-top: 18px; color: var(--brand); font-size: 11px; font-weight: 650; }
.side-edit-link:hover { text-decoration: underline; }

.course-title, .course-desc, .detail-copy, .doc-copy h3, .doc-copy p, .search-result strong, .search-result small { overflow-wrap: anywhere; }

@media (min-width: 721px) and (max-width: 800px) {
  body { padding-bottom: 64px; }
  #app { min-height: calc(100vh - var(--header-height) - 64px); }
  .mobile-nav { position: fixed; right: 0; bottom: 0; left: 0; z-index: 70; display: grid; height: 64px; grid-template-columns: repeat(5, 1fr); border-top: 1px solid var(--border); background: rgba(255,255,255,.98); }
  .mobile-nav a { display: grid; min-width: 0; place-items: center; align-content: center; gap: 3px; color: var(--text-muted); font-size: 12px; }
  .mobile-nav a svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.8; }
  .mobile-nav a.active { color: var(--brand); font-weight: 650; }
  .mobile-nav a:active { background: var(--surface-warm); }
}

@media (max-width: 1024px) {
  .header-inner { gap: 24px; }
  .desktop-nav { gap: 14px; }
  .hero-grid { grid-template-columns: 1fr; gap: 0; }
  .hero-visual { justify-content: center; }
  .visual-main { width: min(100%, 410px); }
  .course-grid { grid-template-columns: repeat(2, 1fr); }
  .qna-replay-grid { grid-template-columns: repeat(2,1fr); }
  .course-detail-grid { grid-template-columns: 350px 1fr; gap: 30px; }
  .watch-layout { grid-template-columns: minmax(0, 1fr) 290px; }
  .live-session-row { grid-template-columns: 72px minmax(240px,1fr) 190px auto; gap: 14px; }
  .studio-layout { grid-template-columns: 380px 1fr; }
  .editor-layout { grid-template-columns: minmax(0,1fr) 310px; }
  .home-course-grid { grid-template-columns: repeat(2,1fr); }
}

@media (max-width: 800px) {
  .desktop-nav { display: none; }
  .hero-grid { grid-template-columns: 1fr; padding: 56px 0; }
  .hero-visual { display: none; }
  .hero::before { width: 28%; opacity: .75; }
  .category-strip { grid-template-columns: repeat(2, 1fr); }
  .category-item:nth-child(2) { border-right: 0; }
  .category-item:nth-child(-n+2) { border-bottom: 1px solid var(--border); }
  .value-banner { grid-template-columns: 1fr; gap: 28px; }
  .community-spotlight { grid-template-columns: 1fr; }
  .course-detail-grid { grid-template-columns: 310px 1fr; }
  .course-content-grid { grid-template-columns: 1fr; }
  .side-card { order: -1; }
  .live-feature { grid-template-columns: 1fr; }
  .live-feature-stage { min-height: 270px; }
  .live-session-row { grid-template-columns: 70px 1fr auto; }
  .live-session-meta { display: none; }
  .room-layout { grid-template-columns: 1fr; }
  .room-side { position: static; }
  .chat-messages { min-height: 240px; max-height: 320px; }
  .studio-layout { grid-template-columns: 1fr; }
  .admin-course-grid { grid-template-columns: repeat(2,1fr); }
  .editor-layout { grid-template-columns: 1fr; }
  .editor-aside { position: static; grid-template-columns: repeat(2,1fr); }
  .account-layout { grid-template-columns: 190px minmax(0,1fr); }
  .account-quick-grid { grid-template-columns: repeat(2,1fr); }
  .admin-setting-grid { grid-template-columns: 1fr; }
  .invite-create-form { grid-template-columns: repeat(3,1fr); }
  .invite-create-form > button { width: 100%; }
  .invite-row { grid-template-columns: 1.2fr 1fr .7fr .8fr; }
  .invite-row > div:nth-child(2) { display: none; }
  .invite-actions { grid-column: 1 / -1; justify-content: flex-start; }
}

@media (max-width: 720px) {
  :root { --header-height: 62px; --control-height: 44px; }
  body { padding-bottom: 64px; font-size: 14px; }
  #app { min-height: calc(100vh - var(--header-height) - 64px); }
  .container { width: min(calc(100% - 28px), var(--container)); }
  .site-header { height: var(--header-height); }
  .brand-mark { width: 38px; height: 38px; }
  .brand-copy strong { font-size: 14px; }
  .brand-copy small, .desktop-only { display: none; }
  .header-actions { gap: 2px; }
  .header-actions .primary-button { display: none; }
  .account-trigger { padding: 3px; }
  .account-trigger-copy, .account-trigger > svg { display: none; }
  .account-avatar { width: 36px; height: 36px; }
  .account-dropdown { position: fixed; top: 58px; right: 10px; width: min(250px,calc(100vw - 20px)); }
  .hero { min-height: auto; }
  .hero-grid { min-height: auto; padding: 50px 0 44px; }
  .hero::before { right: -80px; width: 62%; clip-path: polygon(45% 0,100% 0,100% 100%,0 100%); }
  .hero h1 { max-width: 360px; font-size: clamp(36px, 10.8vw, 44px); line-height: 1.14; }
  .hero-copy > p:not(.eyebrow) { font-size: 14px; line-height: 1.8; }
  .hero-actions { margin-top: 24px; }
  .hero-actions .primary-button, .hero-actions .outline-button { min-height: 46px; padding-inline: 17px; }
  .hero-trust { align-items: flex-start; line-height: 1.55; }
  .section { padding: 48px 0; }
  .section-head { align-items: start; margin-bottom: 22px; }
  .section-head h2 { font-size: 23px; }
  .section-head p { font-size: 13px; }
  .section-link { font-size: 12px; }
  .live-home-section { padding-bottom: 48px; }
  .live-home-card { grid-template-columns: auto 1fr auto; gap: 10px; padding: 12px 14px; }
  .live-home-meta { display: none; }
  .live-home-card b { font-size: 0; }
  .live-home-card b::after { content: "进入 →"; font-size: 11px; }
  .category-item { min-height: 92px; padding: 13px 8px; }
  .category-item span:last-child { font-size: 13px; }
  .course-grid { grid-template-columns: 1fr; gap: 14px; }
  .qna-replay-grid { grid-template-columns: 1fr; gap: 14px; }
  .course-cover { height: 158px; }
  .course-title { min-height: auto; }
  .value-banner { gap: 24px; padding: 28px 22px; border-radius: var(--radius-md); }
  .value-banner h2 { font-size: 24px; }
  .value-list { grid-template-columns: 1fr; }
  .value-item { border-right: 0; border-bottom: 1px solid rgba(255,255,255,.1) !important; }
  .value-item:last-child { border-bottom: 0 !important; }
  .page-hero { padding: 40px 0 32px; }
  .page-hero-grid { align-items: start; flex-direction: column; gap: 22px; }
  .page-hero h1 { font-size: 29px; }
  .hero-stat { width: 100%; justify-content: flex-start; }
  .hero-stat div:first-child { padding-left: 0; border-left: 0; }
  .docs-layout { grid-template-columns: 1fr; gap: 14px; }
  .docs-sidebar { display: flex; overflow-x: auto; padding: 6px; scrollbar-width: none; }
  .docs-sidebar::-webkit-scrollbar { display: none; }
  .docs-sidebar h3 { display: none; }
  .docs-sidebar button { width: auto; min-width: max-content; text-align: center; }
  .doc-row { grid-template-columns: 42px 1fr; padding: 14px; }
  .doc-icon { width: 42px; height: 42px; }
  .doc-action { display: none; }
  .ai-tool-grid { grid-template-columns: 1fr; }
  .ai-tools-guide { grid-template-columns: auto 1fr; align-items: start; }
  .ai-tool-card { grid-template-columns: 58px 1fr; padding: 16px; }
  .ai-tool-icon { width: 58px; height: 58px; border-radius: 13px; font-size: 13px; }
  .ai-tool-feature-grid .ai-tool-card { padding: 20px 16px; }
  .ai-tool-feature-grid .ai-tool-icon { width: 58px; height: 58px; }
  .ai-tool-feature-grid .ai-tool-copy h3 { font-size: 17px; }
  .ai-tool-copy > p { min-height: auto; }
  .ai-tool-actions .small-button { flex: 1; }
  .activate-wrap { padding: 40px 14px 92px; }
  .activate-card { padding: 30px 20px; }
  .activate-card h1 { font-size: 23px; }
  .community-spotlight { border-radius: var(--radius-md); }
  .spotlight-copy { padding: 28px 22px; }
  .spotlight-copy h2 { font-size: 23px; }
  .spotlight-stats div { min-height: 100px; padding: 17px; }
  .live-feature { border-radius: var(--radius-md); }
  .live-feature-copy { padding: 26px 20px; }
  .live-feature-copy > .eyebrow { margin-top: 16px; }
  .live-feature-copy h2 { font-size: 24px; }
  .live-feature-meta { display: grid; gap: 7px; }
  .live-feature-stage { min-height: 240px; }
  .feature-teacher > span { width: 78px; height: 78px; font-size: 26px; }
  .live-list-head { margin-top: 40px; }
  .live-session-row { grid-template-columns: 48px minmax(0,1fr); gap: 12px; min-height: 126px; padding: 15px 13px; }
  .live-date { padding-right: 10px; }
  .live-date strong { font-size: 13px; }
  .live-session-copy h3 { font-size: 14px; }
  .live-session-copy p { display: -webkit-box; overflow: hidden; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
  .live-session-actions { grid-column: 2; justify-items: start; margin-top: -2px; }
  .live-session-actions > .small-button { width: max-content; min-height: 34px; padding-inline: 12px; }
  .live-workflow { grid-template-columns: repeat(2,1fr); }
  .live-workflow div { min-height: 112px; border-bottom: 1px solid var(--border); }
  .live-workflow div:nth-child(2n) { border-right: 0; }
  .live-workflow div:nth-last-child(-n+2) { border-bottom: 0; }
  .live-room-page { padding: 18px 0 28px; }
  .room-heading { align-items: flex-start; flex-direction: column; gap: 12px; }
  .room-heading h1 { font-size: 18px; }
  .room-heading-meta { width: 100%; justify-content: space-between; }
  .room-layout { width: 100%; gap: 10px; margin-top: 16px; }
  .room-stage { border-right: 0; border-left: 0; border-radius: 0; }
  .teacher-stage { min-height: 250px; }
  .live-presentation { min-height: 250px; padding: 22px 16px; }
  .live-whiteboard { height: 300px; }
  .whiteboard-toolbar { right: 8px; bottom: 10px; left: 8px; justify-content: center; overflow-x: auto; transform: none; }
  .whiteboard-toolbar button { flex: 0 0 auto; }
  .whiteboard-zoom { display: none; }
  .whiteboard-topbar > b { display: none; }
  .presentation-ready { grid-template-columns: 48px 1fr; padding: 16px; }
  .presentation-file-icon { width: 48px; height: 56px; }
  .presentation-sync { grid-column: 2; width: max-content; }
  .stage-avatar { width: 82px; height: 82px; font-size: 28px; }
  .guest-grid { grid-template-columns: repeat(2,1fr); }
  .guest-tile { min-height: 92px; }
  .room-controls { width: calc(100% - 28px); overflow-x: auto; margin: 10px auto 0; justify-content: flex-start; padding-inline: 8px; scrollbar-width: none; }
  .room-control { min-width: 62px; }
  .desktop-control { display: none; }
  .room-leave { min-width: max-content; margin-left: 0; }
  .room-replay-note { width: calc(100% - 28px); margin: 10px auto 0; }
  .room-side { width: calc(100% - 28px); margin: 0 auto; }
  .studio-toolbar { align-items: flex-start; flex-direction: column; }
  .studio-toolbar > div:last-child { width: 100%; }
  .studio-toolbar .small-button { flex: 1; }
  .studio-stats { grid-template-columns: repeat(2,1fr); }
  .studio-stats div { min-height: 76px; padding: 13px 16px; border-bottom: 1px solid var(--border); }
  .studio-stats div:nth-child(2n) { border-right: 0; }
  .studio-stats div:nth-last-child(-n+2) { border-bottom: 0; }
  .studio-layout { gap: 14px; }
  .upload-panel { padding: 18px 14px; }
  .media-panel > .panel-heading { padding: 18px 14px 14px; }
  .media-row { grid-template-columns: 40px minmax(0,1fr) auto; gap: 9px; padding: 11px 13px; }
  .media-status { grid-column: 2; }
  .media-row > .text-button { grid-row: 1 / span 2; grid-column: 3; }
  .storage-tip { grid-template-columns: 32px 1fr; margin: 12px; }
  .storage-tip b { grid-column: 2; }
  .studio-course-section { margin-top: 44px; }
  .studio-course-section .section-head { align-items: flex-start; }
  .studio-course-section .section-head .primary-button { display: none; }
  .admin-course-grid { grid-template-columns: 1fr; gap: 13px; }
  .admin-tool-grid { grid-template-columns: 1fr; }
  .admin-tool-card { grid-template-columns: 54px 1fr; padding: 15px; }
  .admin-tool-icon { width: 54px; height: 54px; }
  .admin-tool-card b { grid-column: 2; }
  .admin-course-cover { height: 116px; }
  .account-page { padding-top: 20px; }
  .account-layout { grid-template-columns: 1fr; gap: 14px; }
  .account-sidebar { position: static; overflow: visible; }
  .account-profile-card { display: none; }
  .account-sidebar nav { display: flex; overflow-x: auto; padding: 6px; scrollbar-width: none; }
  .account-sidebar nav::-webkit-scrollbar { display: none; }
  .account-sidebar nav a { min-width: max-content; gap: 8px; }
  .account-sidebar nav a span { display: none; }
  .account-welcome { min-height: 138px; align-items: flex-start; padding: 22px 20px; }
  .account-welcome h2 { font-size: 20px; }
  .account-welcome .primary-button { flex: 0 0 auto; }
  .account-quick-grid { grid-template-columns: repeat(2,1fr); gap: 10px; }
  .account-quick-grid a { padding: 15px; }
  .settings-panel { padding: 18px 15px; }
  .settings-panel-head { align-items: flex-start; margin-bottom: 18px; }
  .settings-panel-head h2 { font-size: 16px; }
  .settings-panel-head > .badge, .settings-panel-head > .status-pill { flex: 0 0 auto; }
  .admin-setting-grid { grid-template-columns: 1fr; gap: 14px; }
  .invite-create-form { grid-template-columns: repeat(2,minmax(0,1fr)); padding: 13px; }
  .invite-create-form > .field:first-child, .invite-create-form > button { grid-column: 1 / -1; }
  .invite-list-head { align-items: flex-start; }
  .invite-list-head span { max-width: 150px; text-align: right; }
  .invite-row { grid-template-columns: 1fr auto; gap: 7px 12px; padding: 15px 2px; }
  .invite-row > div:nth-child(2) { display: grid; }
  .invite-row > div:nth-child(3), .invite-row > div:nth-child(4) { grid-column: 1; }
  .invite-row > .invite-status { grid-row: 1; grid-column: 2; }
  .invite-actions { grid-column: 1 / -1; justify-content: flex-start; padding-top: 5px; }
  .register-page { padding: 28px 14px 92px; place-items: start center; }
  .register-card { padding: 25px 20px; }
  .register-heading h1 { font-size: 24px; }
  .course-editor-page { padding-bottom: 34px; }
  .editor-topbar .container { min-height: 72px; }
  .editor-topbar .container > div:first-child .badge { display: none; }
  .editor-topbar .container > div:first-child strong { font-size: 14px; }
  .editor-topbar .container > div:last-child { gap: 6px; }
  .editor-topbar .small-button { min-height: 36px; padding-inline: 10px; font-size: 11px; }
  .editor-layout { gap: 13px; padding-top: 14px; }
  .editor-panel { padding: 18px 14px; }
  .editor-panel-head { margin-bottom: 18px; }
  .editor-panel-head-action { align-items: flex-start; }
  .editor-panel-head-action .small-button { flex: 0 0 auto; padding-inline: 9px; }
  .editor-fields.two-columns { grid-template-columns: 1fr; }
  .editor-fields .full { grid-column: auto; }
  .cover-editor { grid-template-columns: 1fr; }
  .editor-cover-preview { height: 180px; }
  .access-options { grid-template-columns: 1fr; }
  .course-content-summary { grid-template-columns: repeat(3,1fr); }
  .course-content-summary > div { padding-inline: 9px; }
  .course-content-summary .primary-button { grid-column: 1 / -1; }
  .lesson-editor-row { grid-template-columns: 30px minmax(0,1fr) 32px; }
  .lesson-editor-row label:nth-of-type(2) { grid-column: 2 / 3; }
  .lesson-editor-row .editor-remove { grid-column: 3; grid-row: 1; }
  .outcome-editor-row { grid-template-columns: 30px minmax(0,1fr) 32px; }
  .resource-editor-row { grid-template-columns: 30px 76px minmax(0,1fr) 32px; }
  .resource-editor-row label:nth-of-type(2), .resource-editor-row label:nth-of-type(3) { grid-column: 2 / 4; }
  .resource-editor-row .editor-remove { grid-column: 4; grid-row: 1; }
  .editor-aside { grid-template-columns: 1fr; }
  .course-detail-hero { padding: 30px 0; }
  .course-detail-grid { grid-template-columns: 1fr; gap: 26px; }
  .detail-cover { height: 205px; }
  .detail-copy h1 { font-size: 24px; }
  .tabs { gap: 20px; overflow-x: auto; padding-inline: 18px; }
  .tab-panel { padding: 16px; }
  .lesson-row { grid-template-columns: 30px 1fr auto; padding-inline: 6px; font-size: 12px; }
  .lesson-action { min-height: 38px; }
  .watch-page { min-height: calc(100vh - var(--header-height)); padding-bottom: 142px; }
  .watch-top { height: 42px; }
  .watch-layout { width: 100%; grid-template-columns: 1fr; gap: 12px; padding-top: 0; }
  .video-frame { position: sticky; top: var(--header-height); z-index: 20; aspect-ratio: 16 / 9; border-radius: 0; box-shadow: 0 8px 22px rgba(19,22,28,.16); }
  .watch-info-card { width: calc(100% - 28px); margin: 0 auto; padding: 18px 16px; border-radius: var(--radius-md); }
  .watch-title-row h1 { font-size: 17px; }
  .watch-favorite { min-width: 72px; min-height: 36px; }
  .watch-note { padding: 13px; }
  .watch-playlist { position: static; width: calc(100% - 28px); margin: 0 auto; border-radius: var(--radius-md); }
  .playlist-items { max-height: none; }
  .playlist-item { min-height: 56px; }
  .watch-mobile-actions { position: fixed; right: 0; bottom: 64px; left: 0; z-index: 65; display: grid; height: 52px; grid-template-columns: repeat(3,1fr); border-top: 1px solid var(--border); background: rgba(255,255,255,.98); box-shadow: 0 -6px 18px rgba(31,36,45,.06); }
  .watch-mobile-actions a { display: grid; min-width: 0; place-items: center; color: var(--text-secondary); font-size: 12px; }
  .watch-mobile-actions a:nth-child(2) { color: var(--brand); border-right: 1px solid var(--border); border-left: 1px solid var(--border); font-weight: 700; }
  .watch-mobile-actions a.disabled { opacity: .42; pointer-events: none; }
  .footer-inner { flex-direction: column; gap: 6px; }
  .mobile-nav { position: fixed; right: 0; bottom: 0; left: 0; z-index: 70; display: grid; height: 64px; grid-template-columns: repeat(5, 1fr); border-top: 1px solid var(--border); background: rgba(255,255,255,.98); }
  .mobile-nav a { display: grid; min-width: 0; place-items: center; align-content: center; gap: 3px; color: var(--text-muted); font-size: 12px; }
  .mobile-nav a svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.8; }
  .mobile-nav a.active { color: var(--brand); font-weight: 650; }
  .mobile-nav a:active { background: var(--surface-warm); }
  .modal-backdrop { padding: 68px 12px 20px; }
  .search-panel { padding: 20px 16px; border-radius: var(--radius-md); }
  .search-head h2 { font-size: 19px; }
  .search-input-wrap { height: 48px; }
  .search-input-wrap kbd { display: none; }
  .toast { right: 16px; bottom: 82px; left: 16px; text-align: center; }
  body.watch-mode { padding-bottom: 0; }
  body.watch-mode .mobile-nav { display: none; }
  body.watch-mode .watch-page { padding-bottom: 88px; }
  body.watch-mode .watch-mobile-actions { bottom: 0; }
}

@media (max-width: 380px) {
  .brand-copy strong { font-size: 13px; }
  .hero h1 { font-size: 35px; }
  .hero-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .hero-actions .primary-button, .hero-actions .outline-button { padding-inline: 10px; font-size: 13px; }
  .course-meta { gap: 11px; }
  .detail-actions { align-items: stretch; flex-direction: column; }
  .detail-actions .primary-button { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}