/* ============================================================
   VCHS Studying — styles.css
   Theme: Sky Blue / White — Modern, vibrant, polished
   ============================================================ */

/* ── CSS Custom Properties ──────────────────────────────── */
:root {
  /* Palette */
  --bg-primary:    #F5F0E8;
  --bg-secondary:  #F5F0E8;
  --bg-card:       #FFFFFF;
  --bg-card-hover: #F0EBD8;
  --bg-dark:       #0C1A2E;

  /* Brand Colors */
  --sky-accent:    #0284C7;
  --sky-light:     #38BDF8;
  --sky-dark:      #0369A1;
  --sky-bright:    #0EA5E9;
  --pink:          #EC4899;
  --sky:           #0EA5E9;

  /* Accent (primary interactive) */
  --accent:        #0284C7;
  --accent-light:  rgba(2,132,199,0.10);
  --accent-border: rgba(2,132,199,0.35);
  --accent-dark:   #0369A1;
  --accent-subtle: rgba(2,132,199,0.05);

  /* Text */
  --text-dark:     #0F172A;
  --text-muted:    #64748B;

  /* Semantic state */
  --success:        #059669;
  --success-light:  rgba(5,150,105,0.10);
  --success-border: rgba(5,150,105,0.35);
  --error:          #DC2626;
  --error-light:    rgba(220,38,38,0.10);
  --error-border:   rgba(220,38,38,0.35);

  /* Borders */
  --border:        rgba(2,132,199,0.12);
  --border-subtle: rgba(15,23,42,0.08);

  /* Shadows */
  --shadow-sm:  0 1px 4px rgba(2,132,199,.08), 0 2px 8px rgba(0,0,0,.06);
  --shadow-md:  0 4px 16px rgba(2,132,199,.12), 0 2px 8px rgba(0,0,0,.08);
  --shadow-lg:  0 8px 40px rgba(2,132,199,.15), 0 4px 16px rgba(0,0,0,.10);
  --shadow-xl:  0 20px 60px rgba(2,132,199,.20), 0 8px 24px rgba(0,0,0,.12);

  /* Radii */
  --radius-sm:  8px;
  --radius-md:  14px;
  --radius-lg:  20px;
  --radius-xl:  28px;

  /* Transitions */
  --transition:      0.22s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 0.12s cubic-bezier(0.4, 0, 0.2, 1);

  /* Typography */
  --font-display: 'Cinzel', Georgia, serif;
  --font-body:    'IM Fell English', Georgia, serif;
  --font-hand:    'IM Fell English', Georgia, serif;
  --font-classic: 'IM Fell English', Georgia, serif;
  --font-numbers: 'Inter', system-ui, -apple-system, sans-serif;
  --font-stats:   'Nunito', system-ui, -apple-system, sans-serif;

  /* Gradients */
  --grad-hero:  linear-gradient(135deg, #0369A1 0%, #0284C7 35%, #0EA5E9 65%, #38BDF8 100%);
  --grad-brand: linear-gradient(135deg, #0284C7, #0EA5E9);
  --grad-card:  linear-gradient(145deg, rgba(255,255,255,1) 0%, rgba(238,240,255,0.5) 100%);

  /* Glass */
  --glass-bg:     rgba(255,255,255,0.07);
  --glass-bg-2:   rgba(255,255,255,0.12);
  --glass-border: rgba(255,255,255,0.18);
  --glass-inset:  inset 0 1px 0 rgba(255,255,255,0.25);
}

/* ── Reset & Base ──────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-dark);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ── Utility ────────────────────────────────────────────── */
.hidden { display: none !important; }
.num { font-family: var(--font-numbers); }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* ── Buttons ────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 0.4em; padding: 0.6em 1.5em;
  border: 1.5px solid transparent;
  border-radius: var(--radius-sm);
  font-family: var(--font-display);
  font-size: 0.875rem; font-weight: 700; letter-spacing: 0.01em;
  cursor: pointer; text-decoration: none;
  transition: all var(--transition);
  user-select: none; position: relative;
}
.btn:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
.btn:active:not(:disabled):not([aria-disabled="true"]) {
  transform: scale(0.96) translateY(0) !important;
  box-shadow: none !important;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}
.btn-primary {
  background: var(--grad-brand); color: #fff; border-color: transparent;
  box-shadow: 0 2px 8px rgba(2,132,199,0.35), 0 1px 3px rgba(0,0,0,0.12);
}
.btn-primary:hover {
  background: linear-gradient(135deg, #0369A1, #0284C7);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(2,132,199,0.45), 0 2px 6px rgba(0,0,0,0.12);
}
.btn-secondary {
  background: rgba(2,132,199,0.06); color: var(--accent); border-color: var(--accent-border);
}
.btn-secondary:hover {
  background: var(--accent-light); color: var(--accent-dark);
  border-color: var(--accent);
  transform: translateY(-2px); box-shadow: var(--shadow-sm);
}
.btn-dark {
  background: var(--bg-dark); color: #fff; border-color: var(--bg-dark);
  box-shadow: 0 2px 8px rgba(30,27,75,0.25);
}
.btn-dark:hover {
  background: #0C4A6E; border-color: #0C4A6E;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(30,27,75,0.35);
}
.btn-danger {
  background: rgba(220,38,38,0.08); color: #DC2626; border-color: rgba(220,38,38,0.30);
}
.btn-danger:hover {
  background: rgba(220,38,38,0.15); border-color: rgba(220,38,38,0.5); transform: translateY(-2px);
}
.btn:disabled, .btn[aria-disabled="true"] { opacity: 0.4; cursor: not-allowed; transform: none; }

/* ── Navbar ─────────────────────────────────────────────── */
#navbar {
  position: sticky; top: 0; z-index: 1000;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 2rem; height: 62px;
  background: #F5F0E8;
  border-bottom: 1px solid rgba(0,0,0,0.10);
  box-shadow: 0 1px 8px rgba(0,0,0,.08);
}
.nav-brand {
  font-family: var(--font-display); font-size: 1.15rem; font-weight: 800;
  color: var(--accent-dark);
  text-decoration: none; letter-spacing: -0.01em; cursor: pointer;
  transition: opacity var(--transition);
}
.nav-brand:hover { opacity: 0.85; }
.nav-links { display: flex; gap: 0.25rem; list-style: none; }
.nav-links a {
  font-family: var(--font-body); font-size: 0.85rem; font-weight: 500;
  color: var(--text-muted); text-decoration: none;
  padding: 0.4em 0.85em; border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition); cursor: pointer;
}
.nav-links a:hover, .nav-links a.active { color: var(--text-dark); background: rgba(0,0,0,0.06); }
.nav-auth { display: flex; align-items: center; gap: 0.85rem; }
.nav-auth .btn-secondary {
  background: var(--accent-light); color: var(--accent-dark);
  border-color: var(--accent-border); padding: 0.45em 1.2em; font-size: 0.82rem;
}
.nav-auth .btn-secondary:hover {
  background: rgba(2,132,199,0.15); color: var(--accent-dark);
  border-color: var(--accent); transform: translateY(-1px);
}
#nav-username { font-family: var(--font-body); font-size: 0.875rem; font-weight: 600; color: var(--text-dark); }

/* ── Views ──────────────────────────────────────────────── */
.view { min-height: calc(100vh - 62px); }

/* ── Hero Section ───────────────────────────────────────── */
#hero {
  position: relative; overflow: hidden;
  padding: 6rem 2rem 5.5rem; text-align: center; color: var(--text-dark);
}
.hero-content { position: relative; z-index: 1; max-width: 780px; margin: 0 auto; }
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 0.5em;
  font-family: var(--font-body); font-size: 0.82rem; font-weight: 600;
  color: var(--text-muted); letter-spacing: 0.08em; text-transform: uppercase;
  margin-bottom: 1rem;
  background: rgba(0,0,0,0.05); padding: 0.35em 1em;
  border-radius: 99px; border: 1px solid rgba(0,0,0,0.08);
}
.hero-title {
  font-family: var(--font-display); font-size: clamp(2.4rem, 6vw, 4rem);
  font-weight: 800; letter-spacing: 0.02em; color: var(--text-dark);
  margin-bottom: 1rem; line-height: 1.1;
}
.hero-subtitle {
  font-size: 1.1rem; color: var(--text-muted);
  max-width: 520px; margin: 0 auto 2.5rem; line-height: 1.7; font-weight: 400;
}
.hero-cta { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; margin-bottom: 3.5rem; }
.hero-signup-cta { display: flex; justify-content: center; margin-bottom: 1.25rem; }
.hero-signup-btn { font-size: 1.15rem !important; padding: 0.85em 2.75em !important; box-shadow: 0 6px 28px rgba(2,132,199,0.55) !important; letter-spacing: 0.03em; }
.hero-cta .btn-primary { padding: 0.75em 2em; font-size: 0.95rem; box-shadow: 0 4px 20px rgba(2,132,199,0.5); }
.hero-cta .btn-secondary {
  background: rgba(0,0,0,0.06); color: var(--text-dark);
  border-color: rgba(0,0,0,0.15); padding: 0.75em 2em; font-size: 0.95rem;
}
.hero-cta .btn-secondary:hover {
  background: rgba(0,0,0,0.10); color: var(--text-dark);
  border-color: rgba(0,0,0,0.25); box-shadow: 0 4px 16px rgba(0,0,0,0.10);
}
.hero-stats { display: flex; gap: 1.5rem; justify-content: center; flex-wrap: wrap; }
.stat-bubble {
  background: rgba(0,0,0,0.05); border: 1px solid rgba(0,0,0,0.10);
  border-radius: var(--radius-lg); padding: 1rem 1.75rem;
  box-shadow: var(--shadow-sm);
  animation: floatBubble 4s ease-in-out infinite;
}
.stat-bubble:nth-child(2) { animation-delay: 0.8s; }
.stat-bubble:nth-child(3) { animation-delay: 1.6s; }
@keyframes floatBubble { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-8px); } }
.stat-number { display: block; font-family: var(--font-numbers); font-size: 1.75rem; font-weight: 800; color: var(--text-dark); letter-spacing: 0; line-height: 1.1; }
.stat-number.stat-loading { animation: pulse 1s ease-in-out infinite; }
.stat-label { display: block; font-size: 0.75rem; font-weight: 500; color: var(--text-muted); letter-spacing: 0.06em; text-transform: uppercase; margin-top: 0.15rem; }

/* ── Class Grid Section ─────────────────────────────────── */
#classes-section { padding: 3.5rem 2rem; max-width: 1160px; margin: 0 auto; }
.section-header {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 1rem; margin-bottom: 1.75rem;
}
.section-title { font-family: var(--font-display); font-size: 1.65rem; font-weight: 800; color: var(--text-dark); letter-spacing: 0.04em; }
.section-subtitle { font-family: var(--font-body); font-size: 0.9rem; color: var(--text-muted); margin-top: 0.3rem; font-weight: 400; }
.filter-bar { display: flex; gap: 0.75rem; align-items: center; flex-wrap: wrap; }
.filter-bar input, .filter-bar select {
  font-family: var(--font-body); font-size: 0.875rem; padding: 0.5em 0.9em;
  border: 1.5px solid rgba(2,132,199,0.15); border-radius: var(--radius-sm);
  background: var(--bg-card); color: var(--text-dark);
  transition: border-color var(--transition), box-shadow var(--transition); box-shadow: var(--shadow-sm);
}
.filter-bar input:focus, .filter-bar select:focus {
  outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px rgba(2,132,199,0.10);
}
.filter-bar input { min-width: 210px; }
.filter-bar input::placeholder { color: var(--text-muted); }
.class-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(270px, 1fr)); gap: 1.5rem; }
.class-card {
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.10);
  border-radius: var(--radius-md); padding: 1.75rem;
  display: flex; flex-direction: column; gap: 0.8rem;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  cursor: pointer; background-image: var(--grad-card);
}
.class-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); border-color: rgba(2,132,199,0.25); }
.class-card-icon { font-size: 2.5rem; line-height: 1; }
.class-card-title { font-family: var(--font-display); font-size: 1.05rem; font-weight: 700; color: var(--text-dark); letter-spacing: 0.02em; }
.class-card-question-count { font-family: var(--font-numbers); font-size: 0.9rem; color: var(--text-muted); margin-top: 0.15rem; font-weight: 500; }
.class-card-desc { font-size: 0.85rem; color: var(--text-muted); line-height: 1.55; flex: 1; }

/* ── Subject Badges ─────────────────────────────────────── */
.badge { display: inline-block; padding: 0.25em 0.8em; border-radius: 99px; font-family: var(--font-body); font-size: 0.72rem; letter-spacing: 0.04em; font-weight: 600; }
.badge-science       { background: rgba(5,150,105,0.10);   color: #059669; border: 1.5px solid rgba(5,150,105,0.25); }
.badge-math          { background: rgba(14,165,233,0.10);  color: #0284C7; border: 1.5px solid rgba(14,165,233,0.25); }
.badge-english       { background: var(--accent-light);    color: var(--accent-dark); border: 1.5px solid var(--accent-border); }
.badge-history       { background: rgba(245,158,11,0.10);  color: #B45309; border: 1.5px solid rgba(245,158,11,0.25); }
.badge-language      { background: rgba(168,85,247,0.10);  color: #7C3AED; border: 1.5px solid rgba(168,85,247,0.25); }
.badge-social-studies{ background: rgba(239,68,68,0.10);   color: #DC2626; border: 1.5px solid rgba(239,68,68,0.25); }
.badge-cs            { background: rgba(99,102,241,0.10);  color: #4338CA; border: 1.5px solid rgba(99,102,241,0.25); }
.badge-other         { background: rgba(100,116,139,0.10); color: #475569; border: 1.5px solid rgba(100,116,139,0.25); }

/* ── Leaderboard Preview (Home) ─────────────────────────── */
#leaderboard-preview {
  padding: 3.5rem 2rem;
  border-top: 1px solid rgba(2,132,199,0.10); border-bottom: 1px solid rgba(2,132,199,0.10);
  color: var(--text-dark);
}
#leaderboard-preview .section-title { color: var(--text-dark); }
#leaderboard-preview .section-subtitle { color: var(--text-dark); font-size: 1rem; font-weight: 600; }

/* ── More Classes Banner ────────────────────────────────── */
.classes-more-banner {
  margin: 2rem auto 0; max-width: 960px; padding: 1.5rem 2rem;
  background: linear-gradient(135deg, rgba(2,132,199,0.06) 0%, rgba(14,165,233,0.06) 100%);
  border: 1.5px solid rgba(2,132,199,0.15); border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
}
.classes-more-text { color: var(--text-dark); font-size: 0.95rem; font-weight: 600; margin: 0; }
.classes-more-text::before { content: '✨ '; }

/* ── All Classes View ───────────────────────────────────── */
#classes-view { padding: 2.5rem 2rem 4rem; max-width: 1200px; margin: 0 auto; }
.classes-view-header {
  display: flex; align-items: flex-start; justify-content: space-between;
  gap: 1rem; margin-bottom: 1.5rem; flex-wrap: wrap;
}
.all-classes-filter { margin-bottom: 2rem; }

/* ── Class Detail View ──────────────────────────────────── */
#class-view { padding: 0 0 3rem; }
.class-view-header {
  border-bottom: 1px solid rgba(2,132,199,0.15);
  padding: 2.5rem 2rem 2rem;
  display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap;
}
.class-view-icon { font-size: 3.5rem; line-height: 1; }
.class-view-info { flex: 1; }
.class-view-title { font-family: var(--font-display); font-size: clamp(1.4rem, 3vw, 2rem); font-weight: 800; color: var(--text-dark); margin-bottom: 0.4rem; letter-spacing: 0.02em; }
.class-view-desc { font-size: 0.9rem; color: var(--text-muted); }
.class-view-header .btn-secondary {
  background: var(--accent-light); color: var(--accent-dark);
  border-color: var(--accent-border);
}
.class-view-header .btn-secondary:hover { background: rgba(2,132,199,0.15); color: var(--accent-dark); border-color: var(--accent); }

/* ── Tab System ─────────────────────────────────────────── */
.tab-bar {
  display: flex; background: var(--bg-card);
  border-bottom: 1.5px solid rgba(2,132,199,0.12);
  overflow-x: auto; padding: 0 2rem; gap: 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.tab-btn {
  font-family: var(--font-body); font-size: 0.875rem; font-weight: 600;
  padding: 1rem 1.5rem; background: none; border: none;
  border-bottom: 3px solid transparent;
  color: var(--text-muted); cursor: pointer;
  transition: color var(--transition), border-color var(--transition);
  white-space: nowrap; position: relative; top: 2px; letter-spacing: -0.01em;
}
.tab-btn:hover { color: var(--text-dark); }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-panel { padding: 2rem; max-width: 920px; margin: 0 auto; }

/* ── Quiz Mode Selector ─────────────────────────────────── */
.quiz-mode-selector { display: flex; gap: 1.5rem; justify-content: center; flex-wrap: wrap; padding: 2rem; }
.quiz-unit-filter {
  flex-basis: 100%; display: flex; align-items: center; justify-content: center;
  gap: 0.75rem; margin-bottom: 0.5rem; flex-wrap: wrap;
}
.qbank-filter-label { font-family: var(--font-body); font-size: 0.82rem; font-weight: 600; color: var(--text-muted); letter-spacing: 0.02em; }

/* ── Unit Selector ──────────────────────────────────────── */
.unit-selector { display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; }
.unit-chip {
  display: inline-flex; align-items: center; gap: 0.5em;
  font-family: var(--font-body); font-size: 0.95rem; font-weight: 500;
  padding: 0.55em 1.2em 0.55em 0.95em;
  border: 1.5px solid rgba(2,132,199,0.18); border-radius: 2em;
  background: var(--bg-card); color: var(--text-dark);
  cursor: pointer; transition: all var(--transition); user-select: none;
  box-shadow: var(--shadow-sm);
}
.unit-chip:hover { border-color: var(--accent); background: var(--accent-light); color: var(--accent-dark); }
.unit-chip.active { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; box-shadow: 0 2px 10px rgba(2,132,199,0.30); }
.unit-chip-check {
  flex-shrink: 0; display: inline-flex; align-items: center; justify-content: center;
  width: 17px; height: 17px; border: 1.5px solid currentColor; border-radius: 4px;
  opacity: 0.6; font-size: 11px; font-weight: 900;
  font-family: system-ui, -apple-system, sans-serif; line-height: 1;
  transition: background var(--transition), opacity var(--transition);
}
.unit-chip.active .unit-chip-check { opacity: 1; background: rgba(255,255,255,0.25); }
.unit-chip-label { display: flex; flex-direction: column; align-items: flex-start; line-height: 1.25; }
.unit-chip-count { font-size: 0.72em; opacity: 0.6; font-weight: 400; }
.unit-chip.active .unit-chip-count { opacity: 0.85; }

/* ── Mode Cards ─────────────────────────────────────────── */
.mode-card {
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.10);
  border-radius: var(--radius-md); padding: 2rem 1.75rem;
  text-align: center; cursor: pointer; max-width: 230px; flex: 1;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
  background-image: var(--grad-card);
}
.mode-card:hover { transform: translateY(-5px); border-color: var(--accent); box-shadow: var(--shadow-md); }
.mode-card-icon { font-size: 2.75rem; margin-bottom: 0.75rem; display: block; }
.mode-card-title { font-family: var(--font-display); font-size: 1.05rem; font-weight: 700; color: var(--text-dark); margin-bottom: 0.5rem; letter-spacing: 0.02em; }
.mode-card-desc { font-size: 0.82rem; color: var(--text-muted); line-height: 1.5; }
.quiz-quick-links {
  flex-basis: 100%; display: flex; align-items: center; justify-content: center;
  flex-wrap: wrap; gap: 0.75rem; padding-top: 1rem;
  border-top: 1.5px solid rgba(2,132,199,0.10);
}
.quiz-quick-links-label { font-family: var(--font-body); font-size: 0.82rem; font-weight: 500; color: var(--text-muted); }

/* ── Active Quiz ────────────────────────────────────────── */
.quiz-header {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 0.75rem; margin-bottom: 1.5rem;
  padding: 1rem 1.25rem; background: var(--bg-card);
  border: 1.5px solid rgba(2,132,199,0.10); border-radius: var(--radius-md); box-shadow: var(--shadow-sm);
}
.quiz-progress { font-family: var(--font-numbers); font-size: 0.85rem; font-weight: 500; color: var(--text-muted); }
.quiz-score-display { font-family: var(--font-numbers); font-size: 0.9rem; color: var(--accent); font-weight: 700; }
.quiz-timer {
  font-family: var(--font-numbers); font-size: 1rem; font-weight: 700;
  letter-spacing: 0.05em;
  background: var(--accent-light); padding: 0.2em 0.7em;
  border-radius: var(--radius-sm); border: 1px solid var(--accent-border); color: var(--accent-dark);
}
.quiz-timer.urgent {
  background: rgba(220,38,38,0.10); border-color: rgba(220,38,38,0.30); color: #DC2626;
  animation: pulse 1s ease-in-out infinite;
}
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.55; } }
.quiz-progress-bar {
  width: 100%; height: 8px; background: rgba(2,132,199,0.08);
  border-radius: 4px; overflow: hidden; margin-bottom: 1.75rem;
}
.quiz-progress-fill {
  height: 100%; background: var(--grad-brand); border-radius: 4px;
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}
.quiz-question {
  font-family: var(--font-body); font-size: 1.2rem; font-weight: 500; color: var(--text-dark);
  margin-bottom: 1.5rem; line-height: 1.6; padding: 1.5rem;
  background: var(--bg-card); border-left: 4px solid var(--accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0; box-shadow: var(--shadow-sm);
}
.quiz-code {
  font-family: 'Courier New', Courier, monospace; font-size: 0.95rem; line-height: 1.6;
  background: rgba(0,0,0,0.06); color: var(--text-dark);
  margin-top: 0.85rem; padding: 0.9rem 1.1rem;
  border-radius: var(--radius-sm); border-left: 3px solid var(--accent);
  overflow-x: auto; white-space: pre; text-align: left;
}

/* ── Answer Choices ─────────────────────────────────────── */
.quiz-choices { display: grid; gap: 0.85rem; margin-bottom: 1.5rem; }
.choice-btn {
  display: flex; align-items: center; gap: 0.9rem; padding: 1rem 1.25rem;
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.10);
  border-radius: var(--radius-md); font-family: var(--font-body); font-size: 0.92rem;
  color: var(--text-dark); cursor: pointer; text-align: left;
  transition: all var(--transition); box-shadow: var(--shadow-sm);
}
.choice-btn:hover:not([disabled]) {
  background: var(--accent-light); border-color: var(--accent-border); color: var(--accent-dark);
  transform: translateX(4px); box-shadow: var(--shadow-md);
}
.choice-btn:active:not([disabled]) { transform: scale(0.99) !important; box-shadow: none !important; }
.choice-btn.selected { background: var(--accent-light); border-color: var(--accent); color: var(--accent-dark); box-shadow: 0 0 0 3px var(--accent-subtle); }
.choice-btn.correct { background: var(--success-light); border-color: var(--success-border); color: var(--success); animation: correctPop 0.45s cubic-bezier(0.36, 0.07, 0.19, 0.97) forwards; }
.choice-btn.incorrect { background: var(--error-light); border-color: var(--error-border); color: var(--error); }
.choice-btn.reveal-correct { background: rgba(5,150,105,0.06); border-color: rgba(5,150,105,0.25); }
.choice-label {
  display: flex; align-items: center; justify-content: center;
  width: 30px; height: 30px; border-radius: 8px;
  background: rgba(2,132,199,0.08); color: var(--accent);
  font-family: var(--font-display); font-size: 0.75rem; font-weight: 700;
  flex-shrink: 0; border: 1.5px solid rgba(2,132,199,0.20);
  transition: all var(--transition); position: relative; overflow: hidden;
}
.choice-btn.selected .choice-label { background: var(--accent); color: #fff; border-color: var(--accent); }
.choice-btn.correct .choice-label { background: var(--success); color: #fff; border-color: var(--success); }
.choice-btn.correct .choice-label::after {
  content: '✓'; position: absolute; inset: 0; background: var(--success);
  font-size: 0.85rem; font-weight: 900; text-align: center; line-height: 30px; color: #fff;
}
.choice-btn.incorrect .choice-label { background: var(--error); color: #fff; border-color: var(--error); }
.choice-btn.incorrect .choice-label::after {
  content: '✗'; position: absolute; inset: 0; background: var(--error);
  font-size: 0.85rem; font-weight: 900; text-align: center; line-height: 30px; color: #fff;
}
.quiz-feedback {
  padding: 0.9rem 1.2rem; border-radius: var(--radius-md); font-weight: 600; font-size: 0.9rem;
  margin-bottom: 1rem; border: 1.5px solid; animation: feedbackSlideIn 0.28s ease forwards;
}
.quiz-feedback.correct { background: var(--success-light); border-color: var(--success-border); color: var(--success); }
.quiz-feedback.incorrect { background: var(--error-light); border-color: var(--error-border); color: var(--error); }
.quiz-actions { display: flex; gap: 0.75rem; flex-wrap: wrap; }

/* ── Quiz Results ────────────────────────────────────────── */
.quiz-results { text-align: center; padding: 2.5rem 2rem; animation: questionEnter 0.4s ease forwards; }
.results-icon { font-size: 5rem; margin-bottom: 0.75rem; display: block; animation: bounceIn 0.6s cubic-bezier(0.36, 0.07, 0.19, 0.97) forwards; }
.results-title { font-family: var(--font-display); font-size: 2rem; font-weight: 800; color: var(--text-dark); margin-bottom: 0.5rem; letter-spacing: 0.02em; }
.results-pct {
  font-family: var(--font-numbers); font-size: 4rem; font-weight: 800;
  background: var(--grad-brand); -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; margin-bottom: 0.25rem; letter-spacing: -0.03em;
}
.quiz-results.results-pass .results-pct {
  background: linear-gradient(135deg, var(--success), #34D399);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.quiz-results.results-fail .results-pct {
  background: none; -webkit-text-fill-color: var(--text-muted); color: var(--text-muted);
}

/* ── Quiz Keyframes ─────────────────────────────────────── */
@keyframes correctPop { 0% { transform: scale(1); } 35% { transform: scale(1.025); } 65% { transform: scale(0.99); } 100% { transform: scale(1); } }
@keyframes feedbackSlideIn { from { opacity: 0; transform: translateY(-6px); } to { opacity: 1; transform: translateY(0); } }
@keyframes questionEnter { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
@keyframes bounceIn { 0% { transform: scale(0.6); opacity: 0; } 60% { transform: scale(1.1); opacity: 1; } 80% { transform: scale(0.95); } 100% { transform: scale(1); } }
.quiz-question-enter { animation: questionEnter 0.3s ease forwards; }
.quiz-choices-enter { animation: questionEnter 0.35s ease 0.05s both; }
.results-details { font-size: 0.9rem; color: var(--text-muted); margin-bottom: 2rem; line-height: 1.6; }
.results-actions { display: flex; gap: 0.75rem; justify-content: center; flex-wrap: wrap; }

/* ── Study Guide ─────────────────────────────────────────── */
.guide-list { display: flex; flex-direction: column; gap: 0.85rem; }
.guide-card {
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.10);
  border-radius: var(--radius-md); overflow: hidden; box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition);
}
.guide-card:hover { box-shadow: var(--shadow-md); }
.guide-card-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 1.1rem 1.25rem; cursor: pointer;
  background: rgba(2,132,199,0.03); border-bottom: 1.5px solid rgba(2,132,199,0.08);
  transition: background var(--transition);
}
.guide-card-header:hover { background: rgba(2,132,199,0.07); }
.guide-card-title { font-family: var(--font-display); font-size: 0.95rem; font-weight: 700; color: var(--text-dark); }
.guide-toggle-icon { font-size: 1.1rem; color: var(--accent); transition: transform var(--transition); }
.guide-card.open .guide-toggle-icon { transform: rotate(180deg); }
.guide-card-body { padding: 1.25rem 1.4rem; display: none; }
.guide-card.open .guide-card-body { display: block; }
.guide-bullets { list-style: none; display: flex; flex-direction: column; gap: 0.6rem; }
.guide-bullets li { display: flex; gap: 0.6em; align-items: flex-start; font-size: 0.88rem; color: var(--text-dark); line-height: 1.6; }
.guide-bullets li::before { content: '▸'; color: var(--accent); flex-shrink: 0; margin-top: 0.05em; font-size: 0.85em; }

/* ── Question Bank ──────────────────────────────────────── */
.qbank-filter { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.25rem; flex-wrap: wrap; }
.qbank-filter label { font-family: var(--font-body); font-size: 0.82rem; font-weight: 600; color: var(--text-muted); }
.qbank-count { font-family: var(--font-numbers); font-size: 0.82rem; font-weight: 600; color: var(--accent); margin-left: auto; background: var(--accent-light); padding: 0.2em 0.7em; border-radius: 99px; border: 1px solid var(--accent-border); }
.qbank-list { display: flex; flex-direction: column; gap: 0.85rem; }
.qbank-item {
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.10);
  border-radius: var(--radius-md); padding: 1.1rem 1.25rem; box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition);
}
.qbank-item:hover { box-shadow: var(--shadow-md); }
.qbank-item-header { display: flex; align-items: flex-start; gap: 0.75rem; margin-bottom: 0.7rem; }
.qbank-num {
  font-family: var(--font-display); font-size: 0.72rem; font-weight: 700; color: #fff;
  min-width: 26px; height: 26px; display: flex; align-items: center; justify-content: center;
  background: var(--accent); border-radius: 6px; flex-shrink: 0;
}
.qbank-q { font-size: 0.9rem; color: var(--text-dark); line-height: 1.55; flex: 1; font-weight: 500; }
.qbank-choices { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.35rem 1rem; margin-left: calc(26px + 0.75rem); }
.qbank-choice { font-size: 0.82rem; color: var(--text-muted); display: flex; align-items: center; gap: 0.4em; }
.qbank-choice.answer { color: var(--success); font-weight: 600; }
.qbank-choice.answer::before { content: '✓'; font-size: 0.78rem; }
.qbank-choice:not(.answer)::before { content: '○'; font-size: 0.65rem; opacity: 0.5; }
.qbank-unit-tag { font-family: var(--font-body); font-size: 0.68rem; font-weight: 600; letter-spacing: 0.04em; padding: 0.2em 0.65em; background: var(--accent-light); color: var(--accent-dark); border: 1px solid var(--accent-border); border-radius: 99px; margin-left: auto; white-space: nowrap; }

/* ── Leaderboard Full View ──────────────────────────────── */
#leaderboard-view { padding: 2.5rem 2rem 3rem; max-width: 1000px; margin: 0 auto; }
.leaderboard-header { text-align: center; margin-bottom: 2.5rem; }
.leaderboard-title { font-family: var(--font-display); font-size: clamp(1.6rem, 4vw, 2.2rem); font-weight: 800; color: var(--text-dark); margin-bottom: 0.5rem; letter-spacing: 0.04em; }
.leaderboard-subtitle { font-size: 0.9rem; color: var(--text-muted); }
.leaderboard-table-wrap { overflow-x: auto; border-radius: var(--radius-md); box-shadow: var(--shadow-md); border: 1.5px solid rgba(2,132,199,0.12); }
table.leaderboard-table { width: 100%; border-collapse: collapse; background: var(--bg-card); font-size: 0.875rem; }
.leaderboard-table thead th {
  font-family: var(--font-body); font-size: 0.72rem; font-weight: 700;
  letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-muted);
  background: var(--bg-secondary); padding: 0.9rem 1.1rem; text-align: left;
  white-space: nowrap; border-bottom: 1.5px solid rgba(2,132,199,0.10);
}
.leaderboard-table tbody tr { border-bottom: 1px solid rgba(2,132,199,0.07); transition: background var(--transition); }
.leaderboard-table tbody tr:hover { background: var(--accent-subtle); }
.leaderboard-table td { padding: 0.85rem 1.1rem; color: var(--text-dark); vertical-align: middle; }
.rank-cell { font-family: var(--font-numbers); font-weight: 700; font-size: 1rem; width: 60px; text-align: center; }
.rank-1 .rank-cell { color: #B7860F; font-size: 1.4rem; }
.rank-2 .rank-cell { color: #6B7C93; font-size: 1.25rem; }
.rank-3 .rank-cell { color: #9E5A3A; font-size: 1.15rem; }
.rank-1 { background: rgba(183,134,15,0.06); }
.rank-2 { background: rgba(107,124,147,0.04); }
.rank-3 { background: rgba(158,90,58,0.04); }
.leaderboard-empty { text-align: center; padding: 2.5rem; color: var(--text-muted); font-size: 0.9rem; }
.lb-more-footer { text-align: center; padding: 0.75rem 1rem; font-size: 1.05rem; font-weight: 700; color: var(--text-dark); border-top: 1px solid var(--border); margin-top: -1px; }

/* ── Rank tier badges ───────────────────────────────────── */
.tier-badge { display: inline-flex; align-items: center; gap: 0.3em; padding: 0.25em 0.75em; border-radius: 999px; font-size: 0.75rem; font-weight: 600; letter-spacing: 0.03em; white-space: nowrap; }
.tier-beginner { background: rgba(5,150,105,0.10);   color: #047857; border: 1px solid rgba(5,150,105,0.25); }
.tier-amateur  { background: rgba(14,165,233,0.10);  color: #0284C7; border: 1px solid rgba(14,165,233,0.25); }
.tier-scholar  { background: var(--accent-light);    color: var(--accent-dark); border: 1px solid var(--accent-border); }
.tier-advanced { background: rgba(245,158,11,0.10);  color: #B45309; border: 1px solid rgba(245,158,11,0.25); }
.tier-expert   { background: rgba(239,68,68,0.10);   color: #DC2626; border: 1px solid rgba(239,68,68,0.25); }
.tier-master   { background: linear-gradient(135deg, rgba(2,132,199,0.10), rgba(14,165,233,0.10)); color: var(--accent-dark); border: 1px solid rgba(2,132,199,0.25); font-weight: 700; }
.tier-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.5rem; margin-top: 1rem; }
.tier-pts { font-size: 0.70rem; opacity: 0.75; margin-left: 0.15em; }

/* ── "You" tag pill ─────────────────────────────────────── */
.you-tag { display: inline-block; font-size: 0.68rem; font-weight: 700; letter-spacing: 0.05em; background: var(--accent-light); color: var(--accent); border: 1px solid var(--accent-border); border-radius: 999px; padding: 0.05em 0.55em; vertical-align: middle; margin-left: 0.4em; text-transform: uppercase; }
.lb-you-row { background: var(--accent-subtle) !important; outline: 1.5px solid var(--accent-border); outline-offset: -1px; }
.lb-you-row:hover { background: rgba(2,132,199,0.08) !important; }
.lb-you-banner { display: flex; align-items: center; gap: 1rem; padding: 1rem 1.25rem; background: var(--accent-light); border-bottom: 1px solid var(--accent-border); flex-wrap: wrap; }
.lb-you-banner-preview { border-radius: 12px; border: 1.5px solid var(--accent-border); margin-bottom: 0.75rem; }
.lb-you-rank { font-family: var(--font-numbers); font-size: 1.6rem; font-weight: 800; color: var(--accent); min-width: 3rem; text-align: center; flex-shrink: 0; }
.lb-you-info { display: flex; flex-direction: column; gap: 0.2rem; flex: 1; min-width: 0; }
.lb-you-name { font-size: 1rem; font-weight: 700; color: var(--text-dark); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.lb-you-sub { font-size: 0.78rem; color: var(--text-muted); }
.lb-you-stats { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; flex-shrink: 0; }
.lb-you-pts { font-family: var(--font-stats); font-size: 1.25rem; font-weight: 700; color: var(--accent); }
.lb-pts-cell { font-family: var(--font-stats); font-size: 1rem; font-weight: 700; color: var(--text-dark); }
.lb-quizzes-cell { font-family: var(--font-stats); font-size: 1rem; font-weight: 700; color: var(--text-dark); }
.lb-you-quizzes { font-family: var(--font-stats); font-size: 1rem; color: var(--text-muted); }
.leaderboard-loading { text-align: center; padding: 2rem; color: var(--text-muted); font-size: 0.875rem; }

/* ── Auth Modal ─────────────────────────────────────────── */
#auth-overlay {
  position: fixed; inset: 0; background: rgba(15,23,42,0.70); z-index: 2000;
  display: flex; align-items: center; justify-content: center; padding: 1rem;
  backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px);
}
#auth-modal {
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.15);
  border-radius: var(--radius-lg); padding: 2.25rem;
  width: 100%; max-width: 420px; box-shadow: var(--shadow-xl); position: relative;
}
.modal-close {
  position: absolute; top: 1.1rem; right: 1.1rem;
  background: rgba(2,132,199,0.06); border: 1px solid rgba(2,132,199,0.12);
  border-radius: var(--radius-sm); font-size: 1.1rem; cursor: pointer;
  color: var(--text-muted); line-height: 1; padding: 0.3em 0.45em;
  transition: all var(--transition);
}
.modal-close:hover { color: var(--text-dark); background: rgba(2,132,199,0.12); border-color: rgba(2,132,199,0.25); }
.modal-title { font-family: var(--font-display); font-size: 1.5rem; font-weight: 800; color: var(--text-dark); margin-bottom: 1.5rem; letter-spacing: 0.04em; text-align: center; }
.auth-tabs { display: flex; border-bottom: 1.5px solid rgba(2,132,199,0.12); margin-bottom: 1.5rem; gap: 0; }
.auth-tab { flex: 1; padding: 0.65rem; font-family: var(--font-body); font-size: 0.875rem; font-weight: 600; background: none; border: none; border-bottom: 3px solid transparent; color: var(--text-muted); cursor: pointer; transition: all var(--transition); position: relative; top: 2px; }
.auth-tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.auth-form { display: flex; flex-direction: column; gap: 1.1rem; }
.form-group { display: flex; flex-direction: column; gap: 0.4rem; }
.form-label { font-family: var(--font-body); font-size: 0.82rem; font-weight: 600; letter-spacing: 0.02em; color: var(--text-dark); }
.form-input {
  font-family: var(--font-body); font-size: 0.9rem; padding: 0.65em 0.9em;
  border: 1.5px solid rgba(2,132,199,0.15); border-radius: var(--radius-sm);
  background: var(--bg-primary); color: var(--text-dark);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.form-input::placeholder { color: var(--text-muted); font-weight: 400; }
.form-input:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px rgba(2,132,199,0.10); }
.auth-error { color: var(--error); font-size: 0.82rem; font-weight: 500; padding: 0.6em 0.9em; background: var(--error-light); border: 1.5px solid var(--error-border); border-radius: var(--radius-sm); display: none; }
.auth-error.visible { display: block; }

/* ── Footer ─────────────────────────────────────────────── */
footer { text-align: center; padding: 2rem; background: #F5F0E8; color: var(--text-muted); font-size: 0.82rem; letter-spacing: 0.02em; border-top: 1px solid rgba(0,0,0,0.08); }
.footer-links { display: flex; align-items: center; gap: 0.6rem; margin-top: 0.6rem; flex-wrap: wrap; justify-content: center; }
.footer-sep { color: var(--text-muted); }
.footer-github-link { display: inline-flex; align-items: center; gap: 0.35rem; color: var(--text-muted); text-decoration: none; font-weight: 600; font-size: 0.82rem; transition: color var(--transition); }
.footer-github-link:hover { color: var(--accent); }
.footer-github-icon { flex-shrink: 0; }
.footer-disclaimer-btn { background: none; border: none; color: var(--text-muted); font-family: var(--font-body); font-size: 0.82rem; font-weight: 600; cursor: pointer; padding: 0; letter-spacing: 0.02em; transition: color var(--transition); }
.footer-disclaimer-btn:hover { color: var(--accent); }
/* ── Disclaimer Modal ────────────────────────────────────── */
#disclaimer-overlay {
  position: fixed; inset: 0; background: rgba(15,23,42,0.70); z-index: 2000;
  display: flex; align-items: center; justify-content: center; padding: 1rem;
  backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px);
}
#disclaimer-modal {
  background: var(--bg-card); border: 1.5px solid rgba(2,132,199,0.15);
  border-radius: var(--radius-lg); padding: 2.25rem;
  width: 100%; max-width: 480px; box-shadow: var(--shadow-xl); position: relative;
}
.disclaimer-body { font-size: 0.875rem; color: var(--text-muted); line-height: 1.7; display: flex; flex-direction: column; gap: 0.5rem; }
.disclaimer-body p { margin: 0; }

/* ── Spinner ─────────────────────────────────────────────── */
.spinner { display: inline-block; width: 20px; height: 20px; border: 2.5px solid rgba(2,132,199,0.12); border-top-color: var(--accent); border-radius: 50%; animation: spin 0.7s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ── No-results message ─────────────────────────────────── */
.no-results { text-align: center; color: var(--text-muted); font-size: 0.9rem; padding: 3rem 2rem; }

/* ── Signup Lock / Preview Prompt ──────────────────────── */
.signup-lock { text-align: center; padding: 3.5rem 1.5rem; display: flex; flex-direction: column; align-items: center; gap: 0.85rem; }
.signup-lock-icon { font-size: 3rem; line-height: 1; }
.signup-lock-title { font-family: var(--font-display); font-size: 1.2rem; font-weight: 700; color: var(--text-dark); letter-spacing: 0.02em; }
.signup-lock-note { font-size: 0.85rem; color: var(--text-muted); }
.signup-lock .btn { margin-top: 0.5rem; }

/* ── Section Signup Notice ──────────────────────────────── */
.section-signup-notice {
  display: flex; align-items: center; justify-content: center; gap: 1rem; flex-wrap: wrap;
  margin: 1.5rem auto 0; max-width: 960px; padding: 1rem 1.75rem;
  background: linear-gradient(135deg, rgba(2,132,199,0.07) 0%, rgba(14,165,233,0.07) 100%);
  border: 1.5px solid rgba(2,132,199,0.18); border-radius: var(--radius-md);
}
.section-signup-notice-text { color: var(--text-dark); font-size: 1rem; font-weight: 600; }

/* ── Notification / Toast ───────────────────────────────── */
.toast {
  position: fixed; bottom: 1.5rem; right: 1.5rem;
  background: var(--bg-dark); border: 1px solid rgba(2,132,199,0.25);
  color: rgba(248,250,252,0.9); padding: 0.85rem 1.25rem;
  border-radius: var(--radius-md); font-size: 0.875rem; font-weight: 500;
  box-shadow: var(--shadow-lg); z-index: 3000; opacity: 0;
  transform: translateY(16px) scale(0.96);
  transition: opacity 0.3s ease, transform 0.3s ease;
  pointer-events: none; max-width: 340px;
}
.toast.show { opacity: 1; transform: translateY(0) scale(1); }
.toast.success { border-left: 3px solid var(--success); }
.toast.error   { border-left: 3px solid var(--error); }
.toast.info    { border-left: 3px solid var(--accent); }


/* ── Responsive — Tablet (900px) ───────────────────────── */
@media (max-width: 900px) {
  #navbar { padding: 0 1.25rem; }
  .hero-title { font-size: 2.2rem; }
  .hero-stats { gap: 1rem; }
  #classes-section { padding: 2.5rem 1.25rem; }
  .class-grid { grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 1rem; }
  .tab-panel { padding: 1.5rem; }
  .qbank-choices { grid-template-columns: 1fr; }
  #classes-view { padding: 2rem 1.25rem 3rem; }
  .classes-more-banner { padding: 1.25rem 1.25rem; }
}

/* ── Responsive — Mobile (600px) ───────────────────────── */
@media (max-width: 600px) {
  #navbar { padding: 0 0.85rem; gap: 0.5rem; height: 58px; }
  .nav-links { gap: 0.25rem; }
  .nav-links a { font-size: 0.78rem; padding: 0.3em 0.6em; }
  #nav-username { display: none; }
  #hero { padding: 3.5rem 1rem 3rem; }
  .hero-eyebrow { font-size: 0.75rem; }
  .hero-subtitle { font-size: 0.95rem; margin-bottom: 1.75rem; }
  .hero-cta { flex-direction: column; align-items: center; gap: 0.75rem; margin-bottom: 2.5rem; }
  .hero-cta .btn-primary, .hero-cta .btn-secondary { width: 100%; max-width: 280px; }
  .hero-signup-btn { width: 100%; max-width: 280px; }
  .section-signup-notice { flex-direction: column; text-align: center; }
  .hero-stats { gap: 0.75rem; flex-wrap: wrap; justify-content: center; }
  .stat-bubble { padding: 0.75rem 1.25rem; flex: 1 1 auto; min-width: 90px; text-align: center; }
  .stat-number { font-size: 1.5rem; }
  #classes-section { padding: 2rem 0.85rem; }
  .class-grid { grid-template-columns: 1fr; }
  .class-card { padding: 1.25rem; }
  .section-header { flex-direction: column; align-items: flex-start; }
  .filter-bar { width: 100%; flex-direction: column; gap: 0.5rem; }
  .filter-bar input, .filter-bar select { min-width: 0; width: 100%; }
  .class-view-header { padding: 1.25rem 0.85rem 1.25rem; gap: 0.85rem; }
  .class-view-icon { font-size: 2.5rem; }
  .tab-bar { padding: 0 0.85rem; }
  .tab-btn { padding: 0.85rem 1rem; font-size: 0.82rem; }
  .tab-panel { padding: 1rem 0.85rem; }
  .quiz-mode-selector { flex-direction: column; padding: 1rem; gap: 0.85rem; }
  .mode-card { max-width: 100%; }
  .quiz-header { padding: 0.85rem 1rem; gap: 0.5rem; }
  .quiz-question { font-size: 1rem; padding: 1.1rem; }
  .choice-btn { padding: 0.85rem 1rem; font-size: 0.875rem; }
  .quiz-actions { gap: 0.5rem; }
  .quiz-actions .btn { flex: 1 1 auto; }
  .qbank-choices { margin-left: 0; }
  .qbank-item-header { gap: 0.5rem; }
  .results-pct { font-size: 3rem; }
  .results-title { font-size: 1.5rem; }
  .leaderboard-table thead th, .leaderboard-table td { padding: 0.65rem 0.65rem; font-size: 0.8rem; }
  #auth-modal { padding: 1.75rem 1.25rem; }
  #leaderboard-view { padding: 1.75rem 0.85rem 2.5rem; }
  .classes-more-banner { flex-direction: column; text-align: center; padding: 1.1rem; }
  #classes-view { padding: 1.5rem 0.85rem 3rem; }
  .lb-you-banner { padding: 0.85rem 1rem; gap: 0.75rem; }
  .lb-you-rank { font-size: 1.3rem; }
  .toast { bottom: 1rem; right: 1rem; left: 1rem; max-width: none; }
  .unit-selector { gap: 0.4rem; }
  .quiz-unit-filter { gap: 0.5rem; }
}