/* ============================================================
   LEARNING THEORIES — Shared Stylesheet
   ============================================================ */

/* ---------- 1. CSS Variables ---------- */
:root {
  --color-primary:   #2563EB;
  --color-primary-d: #1D4ED8;
  --color-secondary: #7C3AED;
  --color-success:   #059669;
  --color-warning:   #D97706;
  --color-danger:    #DC2626;
  --color-ai:        #0891B2;
  --color-ai-light:  #E0F2FE;
  --color-teacher:   #92400E;
  --color-teacher-bg:#FEF3C7;
  --color-student:   #1E40AF;
  --color-student-bg:#DBEAFE;

  --bg:        #F8FAFC;
  --bg-card:   #FFFFFF;
  --border:    #E2E8F0;
  --text:      #0F172A;
  --text-muted:#64748B;
  --radius:    10px;
  --shadow:    0 1px 4px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
  --shadow-lg: 0 4px 24px rgba(0,0,0,.12);

  --nav-h: 64px;
  --font-body: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'Cascadia Code', 'Fira Code', monospace;
}

/* ---------- 2. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 16px;
}
a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol { padding-left: 1.5rem; }
img { max-width: 100%; }

/* ---------- 3. Navigation ---------- */
.site-nav {
  position: sticky; top: 0; z-index: 100;
  height: var(--nav-h);
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center;
  padding: 0 1.5rem;
  gap: 1rem;
  box-shadow: 0 1px 4px rgba(0,0,0,.06);
}
.site-nav .brand {
  font-weight: 700; font-size: 1.05rem;
  color: var(--color-primary);
  white-space: nowrap;
}
.site-nav .nav-links {
  display: flex; gap: .25rem; flex-wrap: wrap;
  list-style: none; padding: 0; margin: 0;
  flex: 1;
}
.site-nav .nav-links a {
  display: inline-block;
  padding: .35rem .75rem;
  border-radius: 6px;
  font-size: .82rem; font-weight: 500;
  color: var(--text-muted);
  transition: background .15s, color .15s;
}
.site-nav .nav-links a:hover,
.site-nav .nav-links a.active {
  background: var(--color-student-bg);
  color: var(--color-primary);
  text-decoration: none;
}
.role-toggle {
  display: flex; gap: .5rem; align-items: center;
  flex-shrink: 0;
}
.role-btn {
  padding: .3rem .8rem;
  border-radius: 20px;
  border: 2px solid var(--border);
  background: var(--bg-card);
  cursor: pointer; font-size: .8rem; font-weight: 600;
  transition: all .15s;
}
.role-btn.teacher { color: var(--color-teacher); border-color: var(--color-teacher); }
.role-btn.student { color: var(--color-student); border-color: var(--color-student); }
.role-btn.active.teacher { background: var(--color-teacher-bg); }
.role-btn.active.student { background: var(--color-student-bg); }

/* ---------- 4. Layout ---------- */
.container { max-width: 1120px; margin: 0 auto; padding: 2rem 1.5rem; }
.page-header {
  margin-bottom: 2rem;
  padding-bottom: 1.25rem;
  border-bottom: 2px solid var(--border);
}
.page-header h1 { font-size: 1.9rem; font-weight: 800; }
.page-header .subtitle { color: var(--text-muted); margin-top: .35rem; font-size: 1rem; }
.section-block { margin-bottom: 2.5rem; }
.section-block h2 {
  font-size: 1.3rem; font-weight: 700;
  margin-bottom: 1rem; color: var(--color-primary);
  display: flex; align-items: center; gap: .5rem;
}
.section-block h3 { font-size: 1.1rem; font-weight: 600; margin: 1rem 0 .5rem; }

/* ---------- 5. Cards ---------- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow);
}
.card-grid { display: grid; gap: 1rem; }
.card-grid-2 { grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); }
.card-grid-3 { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
.card h3 { font-size: 1rem; font-weight: 700; margin-bottom: .5rem; }
.card p, .card li { font-size: .92rem; color: var(--text-muted); }

/* Hero card */
.hero-card {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  color: white; border-radius: var(--radius);
  padding: 2.5rem 2rem; margin-bottom: 2rem;
}
.hero-card h1 { font-size: 2rem; font-weight: 800; }
.hero-card .meta { opacity: .85; margin-top: .5rem; font-size: .95rem; }
.hero-card .badges { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: 1rem; }
.hero-card .badge { background: rgba(255,255,255,.2); border-radius: 20px; padding: .25rem .75rem; font-size: .8rem; }

/* ---------- 6. Badges ---------- */
.badge, .tag {
  display: inline-block;
  padding: .2rem .65rem;
  border-radius: 20px; font-size: .75rem; font-weight: 600;
}
.badge-primary { background: var(--color-student-bg); color: var(--color-primary); }
.badge-teacher { background: var(--color-teacher-bg); color: var(--color-teacher); }
.badge-ai      { background: var(--color-ai-light); color: var(--color-ai); }
.badge-success { background: #D1FAE5; color: var(--color-success); }
.badge-warning { background: #FEF3C7; color: var(--color-warning); }
.badge-danger  { background: #FEE2E2; color: var(--color-danger); }
.badge-purple  { background: #EDE9FE; color: var(--color-secondary); }

/* ---------- 7. Tables ---------- */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: .9rem; }
th {
  background: var(--color-student-bg);
  color: var(--color-primary);
  font-weight: 700; text-align: left;
  padding: .75rem 1rem;
  border-bottom: 2px solid var(--color-primary);
}
td { padding: .7rem 1rem; border-bottom: 1px solid var(--border); vertical-align: top; }
tr:hover td { background: #F1F5F9; }

/* ---------- 8. Role visibility ---------- */
.teacher-only, .student-only { display: none; }
body.role-teacher .teacher-only { display: block; }
body.role-student .student-only { display: block; }
body.role-teacher .teacher-only.flex-show { display: flex; }
body.role-student .student-only.flex-show { display: flex; }
.role-banner {
  padding: .5rem 1.5rem;
  font-size: .82rem; font-weight: 600;
  text-align: center;
}
.role-banner.teacher { background: var(--color-teacher-bg); color: var(--color-teacher); }
.role-banner.student { background: var(--color-student-bg); color: var(--color-student); }

/* ---------- 9. AI callout ---------- */
.ai-callout {
  background: var(--color-ai-light);
  border-left: 4px solid var(--color-ai);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.25rem; margin: 1rem 0;
}
.ai-callout .ai-label {
  display: flex; align-items: center; gap: .4rem;
  font-weight: 700; font-size: .85rem; color: var(--color-ai);
  margin-bottom: .4rem;
}
.ai-callout p, .ai-callout li { font-size: .9rem; }

/* ---------- 10. Accordion ---------- */
.accordion { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; margin: .75rem 0; }
.accordion-header {
  display: flex; justify-content: space-between; align-items: center;
  padding: .9rem 1.1rem; cursor: pointer;
  background: var(--bg-card); user-select: none;
  font-weight: 600; font-size: .95rem;
}
.accordion-header:hover { background: #F1F5F9; }
.accordion-header .arrow { transition: transform .25s; font-size: .7rem; }
.accordion-header.open .arrow { transform: rotate(180deg); }
.accordion-body { display: none; padding: 1rem 1.1rem; border-top: 1px solid var(--border); }
.accordion-body.open { display: block; }

/* ---------- 11. Timeline ---------- */
.timeline { position: relative; padding-left: 2rem; }
.timeline::before {
  content: ''; position: absolute; left: .55rem; top: 0; bottom: 0;
  width: 2px; background: var(--border);
}
.timeline-item { position: relative; margin-bottom: 1.5rem; }
.timeline-item::before {
  content: ''; position: absolute; left: -1.55rem; top: .4rem;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--color-primary); border: 2px solid white;
  box-shadow: 0 0 0 2px var(--color-primary);
}
.timeline-item .time-badge {
  display: inline-block; background: var(--color-student-bg);
  color: var(--color-primary); font-size: .78rem; font-weight: 700;
  padding: .15rem .6rem; border-radius: 20px; margin-bottom: .35rem;
}
.timeline-item h3 { font-size: 1rem; font-weight: 700; margin-bottom: .3rem; }

/* ---------- 12. Progress ---------- */
.progress-bar-wrap { background: var(--border); border-radius: 20px; height: 8px; overflow: hidden; }
.progress-bar { height: 100%; background: var(--color-primary); border-radius: 20px; transition: width .4s ease; }
.progress-label { display: flex; justify-content: space-between; font-size: .78rem; color: var(--text-muted); margin-bottom: .25rem; }

/* ---------- 13. Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: .4rem;
  padding: .55rem 1.1rem; border-radius: 8px;
  font-size: .88rem; font-weight: 600; cursor: pointer;
  border: none; transition: all .15s; text-decoration: none;
}
.btn-primary { background: var(--color-primary); color: white; }
.btn-primary:hover { background: var(--color-primary-d); color: white; text-decoration: none; }
.btn-outline { background: transparent; border: 2px solid var(--color-primary); color: var(--color-primary); }
.btn-outline:hover { background: var(--color-student-bg); text-decoration: none; }
.btn-ai { background: var(--color-ai); color: white; }
.btn-ai:hover { background: #0E7490; color: white; text-decoration: none; }
.btn-sm { padding: .3rem .7rem; font-size: .8rem; }

/* ---------- 14. Quiz ---------- */
.quiz-option {
  display: flex; align-items: flex-start; gap: .75rem;
  padding: .75rem 1rem; margin: .4rem 0;
  border: 2px solid var(--border); border-radius: var(--radius);
  cursor: pointer; transition: border-color .15s, background .15s;
  font-size: .92rem;
}
.quiz-option:hover { border-color: var(--color-primary); background: var(--color-student-bg); }
.quiz-option.selected { border-color: var(--color-primary); background: var(--color-student-bg); }
.quiz-option.correct { border-color: var(--color-success); background: #D1FAE5; }
.quiz-option.incorrect { border-color: var(--color-danger); background: #FEE2E2; }
.quiz-feedback { padding: .75rem 1rem; border-radius: var(--radius); margin-top: .75rem; font-size: .9rem; font-weight: 500; }
.quiz-feedback.correct { background: #D1FAE5; color: var(--color-success); }
.quiz-feedback.incorrect { background: #FEE2E2; color: var(--color-danger); }
.quiz-score { font-size: 1.5rem; font-weight: 800; color: var(--color-primary); text-align: center; }

/* ---------- 15. Info / Warning callouts ---------- */
.callout { padding: .9rem 1.1rem; border-radius: var(--radius); margin: .75rem 0; font-size: .9rem; }
.callout-info    { background: #EFF6FF; border-left: 4px solid var(--color-primary); }
.callout-warn    { background: #FFFBEB; border-left: 4px solid var(--color-warning); }
.callout-success { background: #ECFDF5; border-left: 4px solid var(--color-success); }
.callout-teacher { background: var(--color-teacher-bg); border-left: 4px solid var(--color-teacher); }
.callout strong  { display: block; margin-bottom: .3rem; }

/* ---------- 16. Section nav toc ---------- */
.toc-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: .75rem; margin: 1rem 0; }
.toc-card {
  display: flex; flex-direction: column;
  padding: 1rem; border-radius: var(--radius);
  border: 1px solid var(--border); background: var(--bg-card);
  box-shadow: var(--shadow); transition: transform .15s, box-shadow .15s;
  text-decoration: none; color: var(--text);
}
.toc-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); text-decoration: none; color: var(--text); }
.toc-card .toc-num { font-size: .75rem; font-weight: 700; color: var(--color-primary); margin-bottom: .35rem; }
.toc-card .toc-title { font-weight: 700; font-size: .95rem; margin-bottom: .35rem; }
.toc-card .toc-desc { font-size: .8rem; color: var(--text-muted); }

/* ---------- 17. Slides (slides.html only) ---------- */
.slide-stage {
  width: 100%; max-width: 900px; margin: 0 auto;
  aspect-ratio: 16/9; background: white;
  border-radius: var(--radius); box-shadow: var(--shadow-lg);
  overflow: hidden; position: relative;
}
.slide { display: none; width: 100%; height: 100%; flex-direction: column; }
.slide.active { display: flex; }
.slide-header {
  background: var(--color-primary); color: white;
  padding: .6rem 1.5rem; display: flex; justify-content: space-between; align-items: center;
  font-size: .78rem;
}
.slide-body { flex: 1; padding: 2rem 2.5rem; overflow: auto; }
.slide-body h2 { font-size: 1.6rem; font-weight: 800; color: var(--color-primary); margin-bottom: 1rem; }
.slide-body h3 { font-size: 1.1rem; font-weight: 700; color: var(--color-secondary); margin: .75rem 0 .4rem; }
.slide-body p, .slide-body li { font-size: 1rem; line-height: 1.6; }
.slide-body .slide-content { height: 100%; display: flex; flex-direction: column; }
.slide-controls {
  display: flex; justify-content: center; align-items: center;
  gap: 1rem; margin: 1rem 0; flex-wrap: wrap;
}

/* ---------- 18. Responsive ---------- */
@media (max-width: 768px) {
  .site-nav .nav-links { display: none; }
  .hero-card h1 { font-size: 1.5rem; }
  .card-grid-2, .card-grid-3 { grid-template-columns: 1fr; }
  .container { padding: 1rem; }
  .slide-body { padding: 1rem; }
  .slide-body h2 { font-size: 1.2rem; }
  .slide-body p, .slide-body li { font-size: .88rem; }
}

/* ---------- 19. Print ---------- */
@media print {
  .site-nav, .role-toggle, .btn, .slide-controls { display: none !important; }
  body { background: white; font-size: 12pt; }
  .card { box-shadow: none; border: 1px solid #ccc; page-break-inside: avoid; }
}

/* ---------- 20. Utility ---------- */
.flex  { display: flex; }
.flex-col { flex-direction: column; }
.gap-1 { gap: .5rem; }
.gap-2 { gap: 1rem; }
.mt-1  { margin-top: .5rem; }
.mt-2  { margin-top: 1rem; }
.mt-3  { margin-top: 1.5rem; }
.mb-1  { margin-bottom: .5rem; }
.mb-2  { margin-bottom: 1rem; }
.text-center { text-align: center; }
.text-sm  { font-size: .85rem; }
.text-muted { color: var(--text-muted); }
.fw-bold { font-weight: 700; }
.w-full { width: 100%; }
.italic { font-style: italic; }