:root {
  --student-ink: #17231f;
  --student-green: #163e35;
  --student-green-deep: #0f3029;
  --student-green-soft: #dce6df;
  --student-paper: #f6f1e7;
  --student-surface: #fffdf8;
  --student-gold: #d2a24c;
  --student-sage: #7e927f;
  --student-muted: #68736e;
  --student-line: rgba(23, 35, 31, .14);
  --student-shadow: 0 18px 54px rgba(28, 49, 41, .08);
  --student-radius: 18px;
  --student-font: "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --student-serif: "Songti SC", STSong, serif;
  --student-ease: cubic-bezier(.22, 1, .36, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body.student-body,
body.auth-body,
body.player-body {
  margin: 0;
  color: var(--student-ink);
  background: var(--student-paper);
  font-family: var(--student-font);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

button,
input { font: inherit; }

a { color: inherit; }

.student-skip {
  position: fixed;
  top: -60px;
  left: 16px;
  z-index: 100;
  padding: 10px 16px;
  color: #fff;
  background: var(--student-ink);
  border-radius: 8px;
  text-decoration: none;
}

.student-skip:focus { top: 12px; }

.student-sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  z-index: 30;
  width: 248px;
  padding: 34px 20px 24px;
  display: flex;
  flex-direction: column;
  color: var(--student-paper);
  background: var(--student-green);
}

.student-brand {
  min-height: 54px;
  display: flex;
  align-items: center;
  gap: 13px;
  color: inherit;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .02em;
  text-decoration: none;
}

.student-brand img {
  width: 46px;
  height: 46px;
  border-radius: 13px;
}

.student-nav {
  margin-top: 68px;
  display: grid;
  gap: 10px;
}

.student-nav a,
.student-sidebar-footer a {
  min-height: 52px;
  padding: 0 16px;
  display: flex;
  align-items: center;
  gap: 14px;
  color: rgba(246, 241, 231, .76);
  border-radius: 13px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: color .22s ease, background .22s ease, transform .22s var(--student-ease);
}

.student-nav a:hover,
.student-sidebar-footer a:hover,
.student-nav a.is-active {
  color: #fff;
  background: rgba(255, 255, 255, .1);
}

.student-nav a:hover,
.student-sidebar-footer a:hover { transform: translateX(3px); }

.nav-icon {
  width: 21px;
  height: 21px;
  flex: 0 0 21px;
}

.student-sidebar-footer {
  margin-top: auto;
  padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, .22);
}

.student-user-brief {
  margin-bottom: 14px;
  padding: 0 13px;
  display: flex;
  align-items: center;
  gap: 11px;
}

.student-avatar {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  flex: 0 0 36px;
  color: var(--student-green);
  background: var(--student-paper);
  border-radius: 50%;
  font-size: 14px;
  font-weight: 800;
}

.student-user-brief strong,
.student-user-brief small { display: block; }

.student-user-brief strong { font-size: 14px; }

.student-user-brief small {
  color: rgba(246, 241, 231, .58);
  font-size: 11px;
}

.student-mobile-header { display: none; }

.student-main {
  min-height: 100vh;
  margin-left: 248px;
  padding: clamp(34px, 5vw, 72px) clamp(28px, 5vw, 84px) 80px;
}

.student-main-inner {
  width: min(1240px, 100%);
  margin: 0 auto;
}

.student-topline {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 30px;
  margin-bottom: 34px;
}

.student-eyebrow {
  margin: 0 0 8px;
  color: var(--student-gold);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.student-title {
  margin: 0;
  font-size: clamp(34px, 4vw, 56px);
  line-height: 1.18;
  letter-spacing: -.04em;
}

.student-subtitle {
  margin: 10px 0 0;
  color: var(--student-muted);
  font-size: 15px;
}

.student-action,
.student-action-secondary,
.student-icon-action {
  border: 0;
  cursor: pointer;
  text-decoration: none;
  transition: transform .24s var(--student-ease), background .24s ease, border-color .24s ease;
}

.student-action,
.student-action-secondary {
  min-height: 48px;
  padding: 0 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 700;
}

.student-action {
  color: #fff;
  background: var(--student-green);
}

.student-action:hover {
  color: #fff;
  background: var(--student-green-deep);
  transform: translateY(-2px);
}

.student-action-secondary {
  color: var(--student-ink);
  background: transparent;
  border: 1px solid var(--student-line);
}

.student-action-secondary:hover {
  border-color: var(--student-green);
  transform: translateY(-2px);
}

.student-dashboard-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: 20px;
}

.continue-card,
.weekly-card,
.empty-learning,
.course-summary,
.lesson-list,
.auth-card {
  background: var(--student-surface);
  border: 1px solid var(--student-line);
  box-shadow: var(--student-shadow);
}

.continue-card {
  min-height: 280px;
  padding: clamp(28px, 4vw, 48px);
  display: grid;
  grid-template-columns: minmax(160px, .72fr) minmax(0, 1.28fr);
  align-items: center;
  gap: clamp(28px, 4vw, 58px);
  border-radius: var(--student-radius);
}

.continue-art,
.course-art {
  position: relative;
  overflow: hidden;
  background: #e9e6d9;
}

.continue-art {
  aspect-ratio: 4 / 3;
  min-height: 170px;
  border-radius: 10px 40px 10px 10px;
}

.continue-art::before,
.course-art::before {
  content: "";
  position: absolute;
  width: 48%;
  aspect-ratio: 1;
  left: 10%;
  bottom: -12%;
  background: var(--student-green);
  border-radius: 50% 50% 8px 8px;
}

.continue-art::after,
.course-art::after {
  content: "";
  position: absolute;
  width: 19%;
  aspect-ratio: 1;
  top: 14%;
  right: 14%;
  background: var(--student-gold);
  border-radius: 50%;
  box-shadow: -30px 74px 0 10px #98aa92;
}

.continue-content h2 {
  margin: 0;
  font-size: clamp(24px, 2.7vw, 36px);
  line-height: 1.28;
  letter-spacing: -.02em;
}

.continue-meta {
  margin: 12px 0 26px;
  color: var(--student-muted);
  font-size: 14px;
}

.progress-track {
  height: 8px;
  overflow: hidden;
  background: #e8e4d9;
  border-radius: 999px;
}

.progress-value {
  height: 100%;
  background: var(--student-green);
  border-radius: inherit;
}

.progress-caption {
  margin: 8px 0 24px;
  display: flex;
  justify-content: space-between;
  color: var(--student-muted);
  font-size: 12px;
}

.weekly-card {
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  border-radius: var(--student-radius);
}

.weekly-card h2 {
  margin: 0;
  font-size: 18px;
}

.weekly-stat {
  padding: 24px 0;
  border-bottom: 1px solid var(--student-line);
}

.weekly-stat:last-child { border-bottom: 0; }

.weekly-stat strong {
  display: block;
  color: var(--student-green);
  font-size: 42px;
  line-height: 1.1;
  letter-spacing: -.04em;
}

.weekly-stat span {
  color: var(--student-muted);
  font-size: 13px;
}

.student-section { margin-top: 52px; }

.section-title-row {
  margin-bottom: 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.section-title-row h2 {
  margin: 0;
  padding-left: 15px;
  position: relative;
  font-size: 24px;
}

.section-title-row h2::before {
  content: "";
  position: absolute;
  inset: 5px auto 5px 0;
  width: 4px;
  background: var(--student-gold);
  border-radius: 999px;
}

.section-title-row span {
  color: var(--student-muted);
  font-size: 13px;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.course-card-new {
  overflow: hidden;
  display: flex;
  flex-direction: column;
  color: inherit;
  background: var(--student-surface);
  border: 1px solid var(--student-line);
  border-radius: var(--student-radius);
  text-decoration: none;
  transition: transform .28s var(--student-ease), box-shadow .28s ease, border-color .28s ease;
}

.course-card-new:hover {
  color: inherit;
  border-color: rgba(22, 62, 53, .3);
  box-shadow: var(--student-shadow);
  transform: translateY(-5px);
}

.course-cover {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #e9e6d9;
}

.course-cover > img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}

.course-art { width: 100%; height: 100%; }

.course-art.variant-2 { background: #dde5dc; }
.course-art.variant-2::before { left: -5%; bottom: -30%; width: 68%; }
.course-art.variant-2::after { background: #c89842; box-shadow: 28px 75px 0 10px #71896f; }
.course-art.variant-3 { background: #eee7d8; }
.course-art.variant-3::before { left: 48%; bottom: -25%; width: 55%; background: #263f38; }
.course-art.variant-3::after { left: 13%; right: auto; border-radius: 5px; box-shadow: 90px 38px 0 8px #aebba8; }

.course-card-body {
  flex: 1;
  padding: 22px;
  display: flex;
  flex-direction: column;
}

.course-card-body h3 {
  margin: 0 0 8px;
  font-size: 19px;
  line-height: 1.4;
}

.course-description {
  min-height: 45px;
  margin: 0 0 22px;
  display: -webkit-box;
  overflow: hidden;
  color: var(--student-muted);
  font-size: 13px;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.course-card-bottom { margin-top: auto; }

.course-card-meta {
  margin-bottom: 10px;
  display: flex;
  justify-content: space-between;
  color: var(--student-muted);
  font-size: 12px;
}

.course-state {
  margin-top: 15px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--student-muted);
  font-size: 12px;
}

.password-layout {
  max-width: 920px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 20px;
  align-items: start;
}

.password-card,
.password-note {
  padding: clamp(24px, 4vw, 38px);
  background: var(--student-surface);
  border: 1px solid var(--student-line);
  border-radius: var(--student-radius);
  box-shadow: var(--student-shadow);
}

.password-card .student-action { width: 100%; }

.password-note { background: var(--student-green); color: var(--student-paper); }
.password-note > span { color: var(--student-gold); font-size: 30px; }
.password-note h2 { margin: 18px 0 10px; font-size: 19px; }
.password-note p { margin: 0; color: rgba(246,241,231,.66); font-size: 13px; }

.state-dot {
  width: 8px;
  height: 8px;
  background: var(--student-sage);
  border-radius: 50%;
}

.empty-learning {
  padding: clamp(38px, 7vw, 84px) 24px;
  border-radius: var(--student-radius);
  text-align: center;
}

.empty-learning-mark {
  width: 72px;
  height: 72px;
  margin: 0 auto 22px;
  display: grid;
  place-items: center;
  color: var(--student-green);
  background: var(--student-green-soft);
  border-radius: 24px;
  font-size: 30px;
}

.empty-learning h2 { margin: 0; font-size: 24px; }
.empty-learning p { margin: 8px 0 24px; color: var(--student-muted); }

.redeem-dialog {
  width: min(480px, calc(100% - 32px));
  padding: 0;
  color: var(--student-ink);
  background: var(--student-surface);
  border: 1px solid var(--student-line);
  border-radius: 22px;
  box-shadow: 0 36px 90px rgba(10, 35, 27, .24);
}

.redeem-dialog::backdrop {
  background: rgba(9, 30, 24, .58);
  backdrop-filter: blur(6px);
}

.dialog-head {
  padding: 26px 28px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--student-line);
}

.dialog-head h2 { margin: 0; font-size: 21px; }

.student-icon-action {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  color: var(--student-muted);
  background: transparent;
  border-radius: 50%;
  font-size: 24px;
}

.student-icon-action:hover { background: var(--student-paper); }

.dialog-body { padding: 26px 28px 30px; }

.dialog-copy { margin: 0 0 20px; color: var(--student-muted); font-size: 14px; }

.student-field { margin-bottom: 18px; }

.student-field label {
  margin-bottom: 8px;
  display: block;
  font-size: 13px;
  font-weight: 700;
}

.student-input {
  width: 100%;
  height: 52px;
  padding: 0 16px;
  color: var(--student-ink);
  background: #fff;
  border: 1px solid rgba(23, 35, 31, .2);
  border-radius: 12px;
  outline: 0;
  transition: border-color .2s ease, box-shadow .2s ease;
}

.student-input:focus {
  border-color: var(--student-green);
  box-shadow: 0 0 0 4px rgba(22, 62, 53, .1);
}

.student-alert {
  margin: 0 0 18px;
  padding: 12px 14px;
  display: none;
  border-radius: 10px;
  font-size: 13px;
}

.student-alert.alert-danger,
.student-alert.is-error {
  display: block;
  color: #862d28;
  background: #fbe9e7;
  border: 1px solid #f1cbc6;
}

.student-alert.alert-success,
.student-alert.is-success {
  display: block;
  color: #185841;
  background: #e4f2e9;
  border: 1px solid #c8e2d0;
}

.dialog-submit { width: 100%; }

/* Course detail */
.student-breadcrumb {
  margin-bottom: 30px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--student-muted);
  font-size: 13px;
}

.student-breadcrumb a { text-underline-offset: 4px; }

.course-summary {
  padding: clamp(28px, 5vw, 54px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: 48px;
  align-items: end;
  border-radius: var(--student-radius);
}

.course-summary h1 {
  margin: 0;
  font-size: clamp(32px, 4vw, 50px);
  line-height: 1.2;
  letter-spacing: -.035em;
}

.course-summary-copy {
  max-width: 740px;
  margin: 16px 0 0;
  color: var(--student-muted);
  white-space: pre-line;
}

.course-progress-box {
  padding: 22px;
  background: var(--student-paper);
  border-radius: 14px;
}

.course-progress-box strong {
  display: block;
  margin-bottom: 12px;
  color: var(--student-green);
  font-size: 34px;
}

.course-progress-box small { color: var(--student-muted); }

.lesson-list {
  overflow: hidden;
  border-radius: var(--student-radius);
}

.lesson-row {
  min-height: 82px;
  padding: 16px 22px;
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr) auto 28px;
  align-items: center;
  gap: 16px;
  color: inherit;
  border-bottom: 1px solid var(--student-line);
  text-decoration: none;
  transition: background .2s ease, padding-left .22s var(--student-ease);
}

.lesson-row:last-child { border-bottom: 0; }

.lesson-row:hover {
  color: inherit;
  background: #f9f5ec;
  padding-left: 27px;
}

.lesson-index {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  color: var(--student-muted);
  background: var(--student-paper);
  border-radius: 50%;
  font-size: 12px;
  font-weight: 700;
}

.lesson-index.is-complete {
  color: #fff;
  background: var(--student-green);
}

.lesson-name strong,
.lesson-name small { display: block; }
.lesson-name strong { font-size: 15px; }
.lesson-name small { margin-top: 2px; color: var(--student-muted); font-size: 11px; }
.lesson-format {
  margin-right: 7px;
  padding: 2px 7px;
  color: var(--student-green);
  background: var(--student-green-soft);
  border-radius: 999px;
  font-size: 9px;
  font-weight: 700;
}
.lesson-duration { color: var(--student-muted); font-size: 12px; }
.lesson-arrow { color: var(--student-gold); font-size: 20px; }

/* Auth */
.auth-body { min-height: 100vh; }

.auth-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(360px, .9fr) minmax(520px, 1.1fr);
}

.auth-brand-panel {
  position: relative;
  overflow: hidden;
  padding: clamp(34px, 5vw, 72px);
  display: flex;
  flex-direction: column;
  color: var(--student-paper);
  background: var(--student-green);
}

.auth-brand-panel::before {
  content: "";
  position: absolute;
  right: -14vw;
  bottom: -20vw;
  width: 46vw;
  aspect-ratio: 1;
  border: 1px solid rgba(255,255,255,.15);
  border-radius: 50%;
  box-shadow: 0 0 0 70px rgba(255,255,255,.035), 0 0 0 140px rgba(255,255,255,.025);
}

.auth-brand-panel .student-brand { position: relative; z-index: 1; }

.auth-message {
  position: relative;
  z-index: 1;
  margin: auto 0;
}

.auth-message p:first-child {
  margin: 0 0 22px;
  color: var(--student-gold);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .18em;
}

.auth-message h1 {
  max-width: 620px;
  margin: 0;
  font-size: clamp(42px, 5vw, 76px);
  line-height: 1.14;
  letter-spacing: -.045em;
}

.auth-message p:last-child {
  max-width: 520px;
  margin: 26px 0 0;
  color: rgba(246, 241, 231, .68);
  font-size: 15px;
}

.auth-panel {
  padding: 48px clamp(28px, 7vw, 100px);
  display: grid;
  place-items: center;
}

.auth-card {
  width: min(460px, 100%);
  padding: clamp(28px, 5vw, 46px);
  border-radius: 22px;
}

.auth-card h2 {
  margin: 0;
  font-size: 30px;
  letter-spacing: -.025em;
}

.auth-card > p {
  margin: 8px 0 30px;
  color: var(--student-muted);
  font-size: 14px;
}

.auth-card .student-action { width: 100%; margin-top: 4px; }

.auth-foot {
  margin: 24px 0 0;
  color: var(--student-muted);
  font-size: 13px;
  text-align: center;
}

.auth-foot a {
  color: var(--student-green);
  font-weight: 700;
  text-underline-offset: 4px;
}

.auth-support {
  margin: 10px 0 0 !important;
  color: var(--student-muted);
  font-size: 12px !important;
  text-align: center;
}

.auth-home {
  margin-top: 16px;
  display: block;
  color: var(--student-muted);
  font-size: 12px;
  text-align: center;
  text-decoration: none;
}

.auth-home:hover { color: var(--student-green); }

/* Player */
.player-body {
  min-height: 100vh;
  color: var(--student-paper);
  background: #0d1714;
}

.player-header {
  min-height: 70px;
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  background: #101e1a;
  border-bottom: 1px solid rgba(255,255,255,.1);
}

.player-back {
  min-width: 0;
  flex: 1;
  display: flex;
  align-items: center;
  gap: 13px;
  color: var(--student-paper);
  text-decoration: none;
}

.player-back img { width: 36px; height: 36px; border-radius: 10px; }
.player-back span { min-width: 0; overflow: hidden; font-size: 14px; font-weight: 650; text-overflow: ellipsis; white-space: nowrap; }

.player-exit {
  color: rgba(246, 241, 231, .65);
  font-size: 13px;
  text-decoration: none;
}

.player-layout {
  min-height: calc(100vh - 70px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
}

.player-stage { min-width: 0; background: #070b0a; }
.player-stage.is-article { background: #efe9dd; }
.player-stage.is-slides { background: #070b0a; }

.video-ratio {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
}

.video-ratio > * { position: absolute; inset: 0; }

.vod-placeholder {
  display: grid;
  place-items: center;
  padding: 24px;
  text-align: center;
}

.vod-placeholder-mark {
  width: 64px;
  height: 64px;
  margin: 0 auto 18px;
  display: grid;
  place-items: center;
  color: var(--student-green);
  background: var(--student-paper);
  border-radius: 50%;
  font-size: 22px;
}

.vod-placeholder h2 { margin: 0; font-size: 20px; }
.vod-placeholder p { margin: 8px 0 0; color: rgba(246,241,231,.55); font-size: 13px; }

.article-player-scroll {
  min-height: calc(100vh - 164px);
  padding: clamp(24px, 5vw, 68px);
  color: var(--student-ink);
}

.article-learning-content {
  width: min(840px, 100%);
  min-height: 420px;
  margin: 0 auto;
  padding: clamp(28px, 6vw, 70px);
  color: #24302c;
  background: #fffdf8;
  border: 1px solid #ddd5c6;
  border-radius: 20px;
  box-shadow: 0 24px 60px rgba(18,42,35,.12);
  font-size: clamp(16px, 1.55vw, 18px);
  line-height: 1.95;
  overflow-wrap: anywhere;
}

.article-learning-content > :first-child { margin-top: 0; }
.article-learning-content > :last-child { margin-bottom: 0; }
.article-learning-content h2,
.article-learning-content h3 {
  margin: 1.8em 0 .65em;
  color: var(--student-green);
  font-family: var(--student-serif);
  line-height: 1.35;
}
.article-learning-content h2 { font-size: clamp(25px, 3vw, 34px); }
.article-learning-content h3 { font-size: clamp(20px, 2.4vw, 25px); }
.article-learning-content p { margin: 0 0 1.15em; }
.article-learning-content img { display: block; max-width: 100%; height: auto; margin: 30px auto; border-radius: 14px; }
.article-learning-content blockquote { margin: 28px 0; padding: 20px 24px; color: #52605a; background: #f6f1e7; border-left: 3px solid var(--student-gold); }
.article-learning-content a { color: var(--student-green); text-underline-offset: 4px; }
.article-learning-content pre { overflow-x: auto; padding: 18px; background: #f1ece2; border-radius: 10px; }

.article-complete-panel {
  width: min(840px, 100%);
  margin: 20px auto 0;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  color: var(--student-ink);
  background: #fffdf8;
  border: 1px solid #ddd5c6;
  border-radius: 14px;
}
.article-complete-panel strong,
.article-complete-panel span { display: block; }
.article-complete-panel span { margin-top: 4px; color: var(--student-muted); font-size: 12px; }
.article-complete-panel button {
  min-height: 44px;
  padding: 0 20px;
  color: #fff;
  background: var(--student-green);
  border: 0;
  border-radius: 999px;
  font-weight: 700;
}
.article-complete-panel button:disabled { color: var(--student-green); background: #e1e9e3; }

.slides-learning-stage { min-height: calc(100vh - 164px); padding: clamp(18px, 4vw, 46px); display: grid; align-content: center; }
.slides-image-frame {
  width: min(1040px, 100%);
  margin: 0 auto;
  aspect-ratio: 16 / 9;
  display: grid;
  place-items: center;
  overflow: hidden;
  background: #000;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 16px;
  box-shadow: 0 28px 70px rgba(0,0,0,.32);
}
.slides-image-frame img { width: 100%; height: 100%; object-fit: contain; }
.slides-audio-bar {
  width: min(1040px, 100%);
  margin: 16px auto 0;
  padding: 14px 16px;
  display: grid;
  grid-template-columns: minmax(150px, .65fr) minmax(260px, 1fr) auto;
  align-items: center;
  gap: 16px;
  background: #142520;
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 14px;
}
.slides-page-copy span,
.slides-page-copy strong { display: block; }
.slides-page-copy span { margin-bottom: 4px; color: var(--student-gold); font-size: 10px; font-weight: 800; letter-spacing: .12em; }
.slides-page-copy strong { overflow: hidden; font-size: 13px; text-overflow: ellipsis; white-space: nowrap; }
.slides-audio-bar audio { width: 100%; height: 42px; }
.slides-buttons { display: flex; gap: 8px; }
.slides-buttons button {
  min-height: 42px;
  padding: 0 14px;
  color: var(--student-paper);
  background: transparent;
  border: 1px solid rgba(255,255,255,.2);
  border-radius: 999px;
  font-size: 12px;
}
.slides-buttons button:hover { background: rgba(255,255,255,.08); }
.slides-buttons button:disabled { opacity: .38; }
.slides-auto-tip { margin: 10px auto 0; color: rgba(246,241,231,.45); font-size: 11px; text-align: center; }
.slides-empty { min-height: calc(100vh - 164px); }

.player-meta {
  padding: 22px clamp(18px, 3vw, 38px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  background: #101e1a;
  border-top: 1px solid rgba(255,255,255,.08);
}

.player-meta h1 { margin: 0; font-size: clamp(17px, 2vw, 23px); }

.player-controls { display: flex; gap: 10px; }

.player-controls a {
  min-height: 40px;
  padding: 0 16px;
  display: inline-flex;
  align-items: center;
  color: var(--student-paper);
  border: 1px solid rgba(255,255,255,.2);
  border-radius: 999px;
  font-size: 12px;
  text-decoration: none;
}

.player-controls a:hover { background: rgba(255,255,255,.08); }

.player-playlist {
  overflow-y: auto;
  background: #142520;
  border-left: 1px solid rgba(255,255,255,.1);
}

.playlist-head {
  position: sticky;
  top: 0;
  z-index: 2;
  padding: 24px 20px 18px;
  background: #142520;
  border-bottom: 1px solid rgba(255,255,255,.1);
}

.playlist-head h2 { margin: 0; font-size: 16px; }
.playlist-head p { margin: 4px 0 0; color: rgba(246,241,231,.48); font-size: 11px; }

.playlist-list { padding: 10px; }

.playlist-item {
  padding: 13px 12px;
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 9px;
  color: rgba(246,241,231,.68);
  border-radius: 10px;
  font-size: 12px;
  text-decoration: none;
}

.playlist-item:hover,
.playlist-item.is-current {
  color: #fff;
  background: rgba(255,255,255,.08);
}

.playlist-item.is-current { box-shadow: inset 3px 0 0 var(--student-gold); }
.playlist-number { color: var(--student-gold); }
.playlist-item strong,
.playlist-item small { display: block; }
.playlist-item strong { font-size: 12px; font-weight: 650; }
.playlist-item small { margin-top: 4px; color: rgba(246,241,231,.38); font-size: 9px; }

.slides-page-list { margin: 8px 10px 24px; padding-top: 16px; border-top: 1px solid rgba(255,255,255,.1); }
.slides-page-list-head { padding: 0 2px 10px; color: rgba(246,241,231,.42); font-size: 10px; letter-spacing: .08em; }
.slides-page-item {
  width: 100%;
  padding: 8px;
  display: grid;
  grid-template-columns: 70px minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  color: rgba(246,241,231,.62);
  background: transparent;
  border: 0;
  border-radius: 10px;
  text-align: left;
}
.slides-page-item:hover,
.slides-page-item.is-current { color: #fff; background: rgba(255,255,255,.08); }
.slides-page-item.is-current { box-shadow: inset 3px 0 var(--student-gold); }
.slides-page-item img { width: 70px; aspect-ratio: 16 / 9; object-fit: cover; background: #000; border-radius: 5px; }
.slides-page-item strong,
.slides-page-item small { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.slides-page-item strong { font-size: 11px; }
.slides-page-item small { margin-top: 3px; color: rgba(246,241,231,.38); font-size: 9px; }

:focus-visible {
  outline: 3px solid var(--student-gold);
  outline-offset: 3px;
}

@media (max-width: 1120px) {
  .course-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .student-dashboard-grid { grid-template-columns: 1fr; }
  .weekly-card { display: grid; grid-template-columns: 1fr 1fr 1fr; align-items: center; }
  .weekly-card h2 { grid-row: 1; }
  .weekly-stat { padding: 4px 24px; border-bottom: 0; border-left: 1px solid var(--student-line); }
}

@media (max-width: 900px) {
  .student-sidebar { display: none; }

  .student-mobile-header {
    position: sticky;
    top: 0;
    z-index: 30;
    min-height: 68px;
    padding: 10px 18px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    color: var(--student-paper);
    background: rgba(22, 62, 53, .96);
    border-bottom: 1px solid rgba(255,255,255,.14);
    backdrop-filter: blur(16px);
  }

  .student-mobile-header .student-brand { min-width: 0; font-size: 15px; }
  .student-mobile-header .student-brand img { width: 38px; height: 38px; }

  .mobile-actions { display: flex; align-items: center; gap: 8px; }

  .mobile-actions a,
  .mobile-actions button {
    min-height: 42px;
    padding: 0 12px;
    display: inline-flex;
    align-items: center;
    color: var(--student-paper);
    background: rgba(255,255,255,.08);
    border: 0;
    border-radius: 999px;
    font-size: 12px;
    text-decoration: none;
  }

  .student-main { margin-left: 0; padding: 34px 20px 64px; }
  .student-topline { margin-bottom: 28px; }
  .student-topline > .student-action { display: none; }

  .course-summary { grid-template-columns: 1fr; gap: 28px; }
  .password-layout { grid-template-columns: 1fr; }

  .player-layout { min-height: auto; grid-template-columns: 1fr; }
  .player-playlist { max-height: none; border-top: 1px solid rgba(255,255,255,.1); border-left: 0; }
  .playlist-head { position: static; }
  .article-player-scroll,
  .slides-learning-stage { min-height: auto; }
}

@media (max-width: 680px) {
  .student-main { padding-inline: 16px; }
  .student-title { font-size: 34px; }
  .student-subtitle { font-size: 13px; }

  .continue-card { grid-template-columns: 1fr; gap: 24px; padding: 22px; }
  .continue-art { min-height: 145px; aspect-ratio: 16 / 8; }

  .weekly-card { grid-template-columns: 1fr 1fr; padding: 22px; }
  .weekly-card h2 { grid-column: 1 / -1; margin-bottom: 18px; }
  .weekly-stat { padding: 0 16px 0 0; border-left: 0; }
  .weekly-stat + .weekly-stat { padding-left: 16px; border-left: 1px solid var(--student-line); }
  .weekly-stat strong { font-size: 32px; }

  .student-section { margin-top: 42px; }
  .course-grid { grid-template-columns: 1fr; gap: 16px; }
  .course-description { min-height: 0; }

  .lesson-row { grid-template-columns: 38px minmax(0, 1fr) 18px; padding: 14px; gap: 10px; }
  .lesson-duration { display: none; }
  .lesson-row:hover { padding-left: 17px; }

  .auth-shell { grid-template-columns: 1fr; }
  .auth-brand-panel { min-height: 150px; padding: 18px 20px 22px; }
  .auth-brand-panel .student-brand img { width: 38px; height: 38px; }
  .auth-message { margin: 18px 0 0; }
  .auth-message p:first-child { margin-bottom: 10px; font-size: 9px; }
  .auth-message h1 { font-size: 28px; line-height: 1.1; }
  .auth-message p:last-child { display: none; }
  .auth-panel { padding: 14px 12px 32px; align-items: start; }
  .auth-card { padding: 22px 18px; box-shadow: none; }
  .auth-card h2 { font-size: 26px; }
  .auth-card > p { margin-bottom: 20px; }
  .auth-card > .student-eyebrow { margin-bottom: 8px; }
  .auth-card .student-field { margin-bottom: 14px; }
  .auth-foot { margin-top: 18px; }
  .auth-home { margin-top: 12px; }

  .player-header { min-height: 62px; padding: 8px 12px; }
  .player-back img { width: 34px; height: 34px; }
  .player-back span { max-width: 220px; font-size: 12px; }
  .player-meta { align-items: flex-start; flex-direction: column; }
  .player-controls { width: 100%; }
  .player-controls a { flex: 1; justify-content: center; }
  .article-player-scroll { padding: 14px; }
  .article-learning-content { min-height: 0; padding: 25px 20px; border-radius: 14px; }
  .article-complete-panel { align-items: stretch; flex-direction: column; }
  .article-complete-panel button { width: 100%; }
  .slides-learning-stage { padding: 12px; }
  .slides-image-frame { border-radius: 10px; }
  .slides-audio-bar { grid-template-columns: 1fr; gap: 12px; }
  .slides-buttons { width: 100%; }
  .slides-buttons button { flex: 1; }
}

@media (max-width: 420px) {
  .student-mobile-header .student-brand span { display: none; }
}

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