[hidden] { display: none !important; }
/* ══════════════════════════════════════════════════════════════
   VIDYAVERSE — Production CSS
   4 WCAG 2.2 AA Verified Themes • Professional Design
   ══════════════════════════════════════════════════════════════ */

/* ─── CSS CUSTOM PROPERTIES (Theme System) ─────────────────── */
:root, [data-theme="light"] {
  --bg: #FAFAFA; --s1: #FFFFFF; --s2: #F3F4F6; --s3: #E5E7EB;
  --bd: #D1D5DB; --bd2: #E5E7EB;
  --ac: #C2410C; --ac2: #7E22CE; --ac3: #0E7490;
  --gn: #15803D; --rd: #B91C1C; --bl: #1D4ED8; --yl: #A16207;
  --tx: #111827; --tx2: #1F2937; --mt: #4B5563; --dm: #6B7280;
  --input-bg: #FFFFFF; --input-bd: #D1D5DB;
  --nav-bg: #FFFFFF; --nav-shadow: 0 1px 3px rgba(0,0,0,0.08);
  --card-shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --btn-text: #FFFFFF;
  --overlay: rgba(0,0,0,0.5);
  --toast-shadow: 0 4px 20px rgba(0,0,0,0.15);
  /* Contrast verified: --tx on --bg = 17.4:1 ✓, --mt on --bg = 7.1:1 ✓ */
}

[data-theme="pastel"] {
  --bg: #F5F0FF; --s1: #FFFFFF; --s2: #EDE9FE; --s3: #DDD6FE;
  --bd: #C4B5FD; --bd2: #DDD6FE;
  --ac: #7E22CE; --ac2: #C2410C; --ac3: #0E7490;
  --gn: #15803D; --rd: #B91C1C; --bl: #1D4ED8; --yl: #A16207;
  --tx: #1E1B4B; --tx2: #312E81; --mt: #4C1D95; --dm: #6D28D9;
  --input-bg: #FFFFFF; --input-bd: #C4B5FD;
  --nav-bg: #FFFFFF; --nav-shadow: 0 1px 3px rgba(124,58,237,0.1);
  --card-shadow: 0 1px 3px rgba(124,58,237,0.06);
  --btn-text: #FFFFFF;
  /* Contrast: --tx on --bg = 14.2:1 ✓, --mt on --bg = 7.8:1 ✓ */
}

[data-theme="slate"] {
  --bg: #F1F5F9; --s1: #FFFFFF; --s2: #E2E8F0; --s3: #CBD5E1;
  --bd: #94A3B8; --bd2: #CBD5E1;
  --ac: #0369A1; --ac2: #4338CA; --ac3: #0F766E;
  --gn: #15803D; --rd: #B91C1C; --bl: #1D4ED8; --yl: #A16207;
  --tx: #0F172A; --tx2: #1E293B; --mt: #475569; --dm: #64748B;
  --input-bg: #FFFFFF; --input-bd: #94A3B8;
  --nav-bg: #FFFFFF; --nav-shadow: 0 1px 3px rgba(15,23,42,0.08);
  --card-shadow: 0 1px 3px rgba(15,23,42,0.06);
  --btn-text: #FFFFFF;
  /* Contrast: --tx on --bg = 16.2:1 ✓, --mt on --bg = 6.4:1 ✓ */
}

[data-theme="dark"] {
  --bg: #1A1A2E; --s1: #222240; --s2: #2A2A4A; --s3: #333360;
  --bd: #3D3D6B; --bd2: #4A4A7A;
  --ac: #FB923C; --ac2: #A78BFA; --ac3: #22D3EE;
  --gn: #4ADE80; --rd: #F87171; --bl: #60A5FA; --yl: #FBBF24;
  --tx: #F1F5F9; --tx2: #E2E8F0; --mt: #A5B4CF; --dm: #8294B4;
  --input-bg: #2A2A4A; --input-bd: #3D3D6B;
  --nav-bg: #222240; --nav-shadow: 0 1px 3px rgba(0,0,0,0.3);
  --card-shadow: 0 2px 8px rgba(0,0,0,0.2);
  --btn-text: #1A1A2E;
  --overlay: rgba(0,0,0,0.8);
  /* Contrast: --tx on --bg = 13.1:1 ✓, --mt on --bg = 7.2:1 ✓ */
}

/* ─── RESET & BASE ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg); color: var(--tx);
  line-height: 1.6; min-height: 100vh;
  transition: background-color 0.3s, color 0.3s;
}

/* ─── WCAG 2.2 ACCESSIBILITY ──────────────────────────────── */
*:focus-visible {
  outline: 3px solid var(--ac);
  outline-offset: 2px;
  border-radius: 4px;
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}
.skip-link {
  position: absolute; top: -100%; left: 16px;
  background: var(--ac); color: #fff; padding: 12px 24px;
  border-radius: 0 0 8px 8px; font-weight: 700; z-index: 10000;
  text-decoration: none;
}
.skip-link:focus { top: 0; }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); border: 0;
}

/* ─── ANIMATIONS ───────────────────────────────────────────── */
@keyframes fadeUp { 0%{opacity:0;transform:translateY(12px)} 100%{opacity:1;transform:translateY(0)} }
@keyframes fadeIn { 0%{opacity:0} 100%{opacity:1} }
@keyframes slideDown { 0%{opacity:0;transform:translateY(-8px)} 100%{opacity:1;transform:translateY(0)} }
@keyframes pulse { 0%,100%{opacity:0.4} 50%{opacity:1} }
@keyframes float { 0%,100%{transform:translateY(0)} 50%{transform:translateY(-5px)} }
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.anim-fade-up { animation: fadeUp 0.4s ease both; }
.anim-fade-in { animation: fadeIn 0.3s ease both; }

/* ─── LOADING SCREEN ───────────────────────────────────────── */
.loading-screen {
  position: fixed; inset: 0; display: flex; flex-direction: column;
  align-items: center; justify-content: center; background: var(--bg); z-index: 9999;
  transition: opacity 0.4s;
}
.loading-screen.hide { opacity: 0; pointer-events: none; }
.loading-icon { font-size: 56px; margin-bottom: 12px; }
.loading-text {
  font-size: 28px; font-weight: 800; color: var(--ac);
  letter-spacing: -0.5px;
}
.loading-bar {
  width: 120px; height: 4px; background: var(--bd); border-radius: 2px;
  margin-top: 16px; overflow: hidden;
}
.loading-fill {
  height: 100%; width: 30%; background: var(--ac); border-radius: 2px;
  animation: shimmer 1.2s ease infinite;
  background: linear-gradient(90deg, var(--ac), var(--ac2), var(--ac));
  background-size: 200% auto;
}

/* ─── TOAST ────────────────────────────────────────────────── */
.toast {
  position: fixed; top: 16px; left: 50%; transform: translateX(-50%);
  padding: 12px 28px; border-radius: 12px; color: #fff;
  font-weight: 700; font-size: 13px; z-index: 10000;
  box-shadow: var(--toast-shadow); animation: slideDown 0.3s ease;
  max-width: 90vw; text-align: center;
}
.toast.success { background: var(--gn); }
.toast.error { background: var(--rd); }

/* ─── NAV ──────────────────────────────────────────────────── */
.app-nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--nav-bg); box-shadow: var(--nav-shadow);
  border-bottom: 1px solid var(--bd2);
  padding: 10px 16px;
  display: flex; justify-content: space-between; align-items: center;
  transition: background 0.3s;
}
.nav-brand {
  display: flex; align-items: center; gap: 10px;
}
.nav-logo {
  width: 36px; height: 36px; border-radius: 10px;
  background: linear-gradient(135deg, var(--ac), var(--ac2));
  display: flex; align-items: center; justify-content: center;
  font-size: 15px; font-weight: 900; color: #fff;
}
.nav-title { font-size: 16px; font-weight: 800; color: var(--tx); }
.nav-subtitle { font-size: 10px; color: var(--dm); }
.nav-actions { display: flex; gap: 6px; align-items: center; }

/* ─── THEME TOGGLE ─────────────────────────────────────────── */
.theme-toggle {
  display: flex; gap: 3px; padding: 3px;
  background: var(--s2); border-radius: 10px; border: 1px solid var(--bd);
}
.theme-btn {
  width: 34px; height: 34px; border-radius: 7px;
  border: 2px solid transparent; background: transparent;
  cursor: pointer; font-size: 14px;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.2s;
}
.theme-btn.active {
  border-color: var(--ac); background: var(--s1);
}
.theme-btn:hover { background: var(--s3); }

/* ─── BUTTONS ──────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 12px 24px; border-radius: 10px; border: none;
  font-family: inherit; font-size: 14px; font-weight: 700;
  cursor: pointer; transition: all 0.2s; letter-spacing: 0.2px;
  min-height: 44px; min-width: 44px; /* WCAG 2.2 target size */
  text-decoration: none; gap: 6px;
}
.btn-primary {
  background: var(--ac); color: var(--btn-text);
  box-shadow: 0 2px 8px color-mix(in srgb, var(--ac) 30%, transparent);
}
.btn-primary:hover { filter: brightness(1.1); transform: translateY(-1px); }
.btn-secondary {
  background: transparent; color: var(--ac);
  border: 2px solid var(--ac);
}
.btn-ghost {
  background: var(--s2); color: var(--tx2);
  border: 1px solid var(--bd);
}
.btn-ghost:hover { background: var(--s3); }
.btn-success { background: var(--gn); color: #fff; }
.btn-danger { background: var(--rd); color: #fff; }
.btn-sm { padding: 8px 16px; font-size: 12px; }
.btn-full { width: 100%; }
.btn-icon { padding: 10px; font-size: 16px; }

/* ─── CARDS ────────────────────────────────────────────────── */
.card {
  background: var(--s1); border: 1px solid var(--bd2);
  border-radius: 14px; padding: 20px;
  box-shadow: var(--card-shadow);
  transition: all 0.25s;
}
.card-hover:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px color-mix(in srgb, var(--ac) 10%, transparent);
  border-color: color-mix(in srgb, var(--ac) 25%, transparent);
}
.card-top-accent { border-top: 4px solid var(--ac); }

/* ─── INPUTS ───────────────────────────────────────────────── */
.input-group { margin-bottom: 16px; }
.input-label {
  display: block; font-size: 12px; font-weight: 600;
  color: var(--tx2); margin-bottom: 6px;
  text-transform: uppercase; letter-spacing: 0.5px;
}
.input-field {
  width: 100%; padding: 12px 16px;
  background: var(--input-bg); border: 2px solid var(--input-bd);
  border-radius: 10px; color: var(--tx); font-family: inherit;
  font-size: 14px; outline: none; transition: border-color 0.2s;
  min-height: 44px; /* WCAG 2.2 */
}
.input-field:focus { border-color: var(--ac); }
.input-field::placeholder { color: var(--dm); }
.input-error { border-color: var(--rd) !important; }
.error-text { color: var(--rd); font-size: 11px; margin-top: 4px; font-weight: 500; }

/* ─── LAYOUT ───────────────────────────────────────────────── */
.container { max-width: 840px; margin: 0 auto; padding: 16px; }
.page-center {
  min-height: 100vh; display: flex; align-items: center;
  justify-content: center; padding: 20px;
}
.grid { display: grid; gap: 12px; }
.grid-auto { grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.flex { display: flex; }
.flex-between { justify-content: space-between; }
.flex-center { align-items: center; }
.gap-4 { gap: 4px; } .gap-6 { gap: 6px; } .gap-8 { gap: 8px; } .gap-10 { gap: 10px; }

/* ─── TYPOGRAPHY ───────────────────────────────────────────── */
.text-xs { font-size: 10px; } .text-sm { font-size: 12px; }
.text-base { font-size: 14px; } .text-lg { font-size: 16px; }
.text-xl { font-size: 20px; } .text-2xl { font-size: 24px; }
.text-3xl { font-size: 32px; }
.font-bold { font-weight: 700; } .font-extra { font-weight: 800; }
.text-muted { color: var(--mt); } .text-dim { color: var(--dm); }
.text-ac { color: var(--ac); } .text-gn { color: var(--gn); }
.text-rd { color: var(--rd); } .text-bl { color: var(--bl); }
.mono { font-family: 'IBM Plex Mono', monospace; }

/* ─── SEARCH ───────────────────────────────────────────────── */
.search-box {
  position: relative; margin-bottom: 18px;
}
.search-input {
  width: 100%; padding: 14px 18px 14px 44px;
  background: var(--input-bg); border: 2px solid var(--input-bd);
  border-radius: 14px; color: var(--tx); font-size: 14px;
  font-family: inherit; outline: none; min-height: 48px;
}
.search-input:focus { border-color: var(--ac); }
.search-icon {
  position: absolute; left: 16px; top: 50%; transform: translateY(-50%);
  font-size: 16px; color: var(--dm); pointer-events: none;
}
.search-results {
  position: absolute; top: 100%; left: 0; right: 0;
  background: var(--s1); border: 1px solid var(--bd);
  border-radius: 14px; max-height: 260px; overflow: auto;
  z-index: 99; margin-top: 6px; box-shadow: 0 8px 32px rgba(0,0,0,0.1);
}
.search-item {
  padding: 12px 18px; border-bottom: 1px solid var(--bd2);
  cursor: pointer; font-size: 12px; min-height: 44px;
  display: flex; align-items: center; gap: 8px;
}
.search-item:hover { background: var(--s2); }

/* ─── BREADCRUMB BUTTONS ───────────────────────────────────── */
.back-btn {
  background: none; border: none; color: var(--ac);
  cursor: pointer; font-size: 13px; font-weight: 600;
  padding: 8px 0; font-family: inherit; min-height: 44px;
  display: inline-flex; align-items: center;
}

/* ─── LIST ITEMS (chapters, topics) ────────────────────────── */
.list-item {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 16px; background: var(--s1);
  border: 1px solid var(--bd2); border-radius: 12px;
  cursor: pointer; transition: all 0.2s; margin-bottom: 8px;
  min-height: 56px;
}
.list-item:hover {
  border-color: color-mix(in srgb, var(--ac) 30%, transparent);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.list-number {
  width: 40px; height: 40px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-weight: 800; flex-shrink: 0;
  font-family: 'IBM Plex Mono', monospace;
}
.list-content { flex: 1; min-width: 0; }
.list-title { font-size: 14px; font-weight: 600; color: var(--tx); }
.list-meta { font-size: 11px; color: var(--dm); margin-top: 2px; }
.av-badge {
  padding: 6px 12px; border-radius: 8px; font-size: 10px;
  font-weight: 700; font-family: 'IBM Plex Mono', monospace;
  flex-shrink: 0; border: 1px solid;
}

/* ─── STAT CARDS ───────────────────────────────────────────── */
.stat-card { text-align: center; padding: 16px; }
.stat-icon { font-size: 22px; margin-bottom: 4px; }
.stat-value { font-size: 22px; font-weight: 900; }
.stat-label { font-size: 10px; color: var(--mt); margin-top: 2px; }

/* ─── AV PLAYER ────────────────────────────────────────────── */
.av-player-overlay {
  position: fixed; inset: 0; background: var(--bg);
  z-index: 1000; display: flex; flex-direction: column;
  overflow: hidden;
}
.av-header {
  padding: 12px 16px; background: var(--nav-bg);
  border-bottom: 1px solid var(--bd);
  display: flex; justify-content: space-between; align-items: center;
}
.av-scene {
  height: 180px; position: relative; overflow: hidden;
  display: flex; align-items: center; justify-content: center;
  border-bottom: 1px solid var(--bd);
}
.av-controls {
  padding: 10px 16px; background: var(--nav-bg);
  border-bottom: 1px solid var(--bd);
  display: flex; gap: 8px; flex-wrap: wrap; align-items: center;
}
.av-body { flex: 1; overflow: auto; padding: 16px; }
.word-highlight {
  transition: all 0.12s;
  padding: 0 1px; border-radius: 4px;
}
.word-current {
  color: var(--ac) !important; font-weight: 800;
  background: color-mix(in srgb, var(--ac) 10%, transparent);
  padding: 3px 5px; border-bottom: 2px solid var(--ac);
}
.word-done { color: var(--tx); }
.word-pending { color: var(--dm); }

.progress-bar {
  height: 5px; background: var(--bd2); border-radius: 3px;
  overflow: hidden; margin: 12px 0;
}
.progress-fill {
  height: 100%; border-radius: 3px; transition: width 0.2s;
  background: linear-gradient(90deg, var(--ac), var(--ac2));
}

/* AI Buttons */
.ai-btn-group {
  display: flex; gap: 8px; padding-top: 14px;
  border-top: 1px solid var(--bd); margin-top: 12px;
}
.ai-btn {
  flex: 1; padding: 14px; border-radius: 14px;
  cursor: pointer; text-align: center;
  border: 2px solid; transition: all 0.2s;
  min-height: 44px; background: transparent;
  font-family: inherit;
}
.ai-panel {
  margin: 16px 0; padding: 16px; border-radius: 16px;
  animation: fadeUp 0.3s ease;
}
.ai-panel-text {
  font-size: 14px; line-height: 2; white-space: pre-wrap;
  color: var(--tx);
}

/* ─── FORMS IN MODALS ──────────────────────────────────────── */
.modal-overlay {
  position: fixed; inset: 0; background: var(--overlay);
  z-index: 500; display: flex; align-items: center;
  justify-content: center; padding: 20px;
}
.modal-card {
  background: var(--s1); border-radius: 20px; padding: 28px;
  width: 100%; max-width: 420px; animation: fadeUp 0.3s ease;
  border: 1px solid var(--bd2); box-shadow: 0 16px 48px rgba(0,0,0,0.15);
}

/* ─── ADMIN TABS ───────────────────────────────────────────── */
.admin-tabs {
  display: flex; gap: 6px; overflow-x: auto; padding: 8px 16px;
  border-bottom: 1px solid var(--bd); background: var(--nav-bg);
  -webkit-overflow-scrolling: touch;
}
.admin-tab {
  padding: 8px 14px; border-radius: 8px; border: 1px solid var(--bd);
  cursor: pointer; font-size: 11px; font-weight: 500;
  background: var(--s1); color: var(--mt); white-space: nowrap;
  font-family: inherit; min-height: 40px;
  transition: all 0.2s;
}
.admin-tab.active {
  border-color: var(--ac); background: color-mix(in srgb, var(--ac) 10%, transparent);
  color: var(--ac); font-weight: 700;
}

/* ─── PLAN CARDS ───────────────────────────────────────────── */
.plan-price { font-size: 30px; font-weight: 900; color: var(--ac); }
.plan-duration { font-size: 12px; color: var(--dm); }
.plan-features { font-size: 11px; color: var(--mt); line-height: 1.6; margin: 8px 0 14px; }

/* ─── CLASS ACCESS BUTTONS (Admin) ─────────────────────────── */
.access-btn {
  padding: 5px 10px; border-radius: 6px; cursor: pointer;
  font-size: 10px; font-family: 'IBM Plex Mono', monospace;
  font-weight: 600; min-width: 32px; min-height: 32px;
  transition: all 0.2s; border: 2px solid;
}
.access-btn.active {
  border-color: var(--gn);
  background: color-mix(in srgb, var(--gn) 12%, transparent);
  color: var(--gn);
}
.access-btn.inactive {
  border-color: var(--bd); background: transparent; color: var(--dm);
}

/* ─── RESPONSIVE ───────────────────────────────────────────── */
@media (max-width: 640px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-auto { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); }
  .text-3xl { font-size: 26px; }
  .container { padding: 12px; }
}
@media (max-width: 380px) {
  .grid-3 { grid-template-columns: 1fr; }
  .theme-toggle { gap: 2px; padding: 2px; }
  .theme-btn { width: 30px; height: 30px; }
}

/* ─── HIGH CONTRAST MODE ───────────────────────────────────── */
@media (prefers-contrast: high) {
  :root {
    --bd: #000000; --tx: #000000; --mt: #000000;
    --card-shadow: 0 0 0 2px #000;
  }
  .btn { border: 2px solid currentColor; }
}