/* =============================================
   AI-Native PM Mastercourse — Shared Stylesheet
   Dark Theme | Ross Thomas PM
   ============================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:         #0f1117;
  --surface:    #1a1d27;
  --surface2:   #222537;
  --border:     #2a2d3a;
  --border2:    #363a50;
  --accent:     #6c63ff;
  --accent-dim: #4b44c4;
  --accent-glow:#6c63ff33;
  --success:    #22c55e;
  --success-dim:#16a34a22;
  --warning:    #f59e0b;
  --warning-dim:#f59e0b22;
  --danger:     #ef4444;
  --danger-dim: #ef444422;
  --text:       #e2e4ed;
  --text-muted: #8b8fa8;
  --text-dim:   #5a5e75;
  --code-bg:    #12141e;
  --module-0:   #6c63ff;
  --module-1:   #818cf8;
  --module-2:   #34d399;
  --module-3:   #60a5fa;
  --module-4:   #f472b6;
  --module-5:   #fb923c;
  --module-6:   #a78bfa;
  --module-7:   #38bdf8;
  --module-8:   #4ade80;
  --module-9:   #fbbf24;
  --module-10:  #e879f9;
  --module-11:  #f87171;
  --module-12:  #6c63ff;
  --radius:     10px;
  --radius-lg:  16px;
  --shadow:     0 4px 24px rgba(0,0,0,0.4);
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', sans-serif;
  font-size: 16px;
  line-height: 1.7;
  min-height: 100vh;
}

/* ── Typography ── */
h1, h2, h3, h4, h5 { font-weight: 600; line-height: 1.3; color: #fff; }
h1 { font-size: 2.4rem; }
h2 { font-size: 1.8rem; margin-top: 2.5rem; margin-bottom: 1rem; }
h3 { font-size: 1.3rem; margin-top: 2rem; margin-bottom: 0.75rem; color: #c4c8e0; }
h4 { font-size: 1.1rem; margin-top: 1.5rem; margin-bottom: 0.5rem; color: #a0a4bc; }
p  { margin-bottom: 1rem; }
a  { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: #a89fff; text-decoration: underline; }
strong { color: #fff; font-weight: 600; }
em { color: #c4c8e0; font-style: italic; }
ul, ol { margin: 0.5rem 0 1rem 1.5rem; }
li { margin-bottom: 0.4rem; }
hr { border: none; border-top: 1px solid var(--border); margin: 2.5rem 0; }
blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.75rem 1.25rem;
  margin: 1.5rem 0;
  background: var(--surface);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-muted);
  font-style: italic;
}

/* ── Code ── */
code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85em;
  background: var(--code-bg);
  color: #a89fff;
  padding: 0.15em 0.45em;
  border-radius: 4px;
  border: 1px solid var(--border);
}
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  margin: 1.25rem 0;
}
pre code {
  background: none;
  border: none;
  padding: 0;
  color: #c4c8e0;
  font-size: 0.88rem;
}

/* ── Tables ── */
.table-wrap { overflow-x: auto; margin: 1.25rem 0; }
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}
thead { background: var(--surface2); }
th {
  padding: 0.75rem 1rem;
  text-align: left;
  font-weight: 600;
  color: #c4c8e0;
  border-bottom: 2px solid var(--border2);
  white-space: nowrap;
}
td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--surface2); }
table strong { color: var(--accent); }

/* ── Navbar ── */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(15,17,23,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.nav-logo {
  font-weight: 700;
  font-size: 1rem;
  color: #fff;
  text-decoration: none;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-logo .logo-accent { color: var(--accent); }
.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}
.nav-links::-webkit-scrollbar { display: none; }
.nav-links a {
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 500;
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
  white-space: nowrap;
  transition: all 0.2s;
  text-decoration: none;
}
.nav-links a:hover, .nav-links a.active {
  color: #fff;
  background: var(--surface2);
}
.nav-links a.active { color: var(--accent); }

/* ── Page Layout ── */
.page-wrap {
  max-width: 900px;
  margin: 0 auto;
  padding: 3rem 2rem 6rem;
}
.page-wrap.wide { max-width: 1100px; }

/* ── Module Header ── */
.module-header {
  border-radius: var(--radius-lg);
  padding: 2.5rem 2.5rem 2rem;
  margin-bottom: 2.5rem;
  position: relative;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--border);
}
.module-header::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--mod-color, var(--accent));
}
.module-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--accent-glow);
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 20px;
  padding: 0.25rem 0.75rem;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
}
.module-header h1 { font-size: 2rem; margin-bottom: 0.5rem; }
.module-meta {
  display: flex;
  gap: 1.5rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}
.module-meta span {
  color: var(--text-muted);
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* ── Learning Objectives Box ── */
.objectives-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  margin-bottom: 2.5rem;
}
.objectives-box h3 {
  color: var(--accent);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0 0 1rem;
}
.objectives-box ul { margin: 0; list-style: none; padding: 0; }
.objectives-box li {
  padding: 0.35rem 0;
  padding-left: 1.5rem;
  position: relative;
  color: var(--text-muted);
  font-size: 0.95rem;
}
.objectives-box li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--success);
  font-weight: 700;
}

/* ── Lesson Section ── */
.lesson {
  margin-bottom: 3rem;
}
.lesson-title {
  font-size: 1.4rem;
  color: #fff;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.75rem;
  margin-bottom: 1.5rem;
}
.lesson-number {
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 600;
  display: block;
  margin-bottom: 0.3rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ── Key Concept Box ── */
.key-concept {
  background: linear-gradient(135deg, #1a1d27, #1e2030);
  border: 1px solid var(--border2);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 1.5rem 0;
}
.key-concept .kc-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--warning);
  margin-bottom: 0.5rem;
}

/* ── Callout Boxes ── */
.callout {
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}
.callout-icon { font-size: 1.2rem; flex-shrink: 0; margin-top: 0.1rem; }
.callout-body { flex: 1; }
.callout-body strong { display: block; margin-bottom: 0.3rem; }
.callout.info    { background: #1a1d3a; border: 1px solid #3a3f6a; }
.callout.warning { background: var(--warning-dim); border: 1px solid #7a5a0a; }
.callout.success { background: var(--success-dim); border: 1px solid #166534; }
.callout.danger  { background: var(--danger-dim);  border: 1px solid #7f1d1d; }
.callout.info    .callout-body strong { color: #818cf8; }
.callout.warning .callout-body strong { color: var(--warning); }
.callout.success .callout-body strong { color: var(--success); }
.callout.danger  .callout-body strong { color: var(--danger); }

/* ── Lab Section ── */
.lab-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  margin: 3rem 0;
  overflow: hidden;
}
.lab-header {
  background: linear-gradient(90deg, #1e1a3d, #1a1d27);
  border-bottom: 1px solid var(--border);
  padding: 1.5rem 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}
.lab-badge {
  background: var(--accent);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
}
.lab-header h2 {
  margin: 0;
  font-size: 1.3rem;
  color: #fff;
}
.lab-body { padding: 2rem; }
.lab-scenario {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2rem;
  font-size: 0.93rem;
  color: var(--text-muted);
  font-style: italic;
}
.lab-step {
  margin: 1.5rem 0;
  padding: 1.25rem 1.5rem;
  background: var(--surface2);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.step-label {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

/* ── Deliverable Checklist ── */
.deliverable-box {
  background: var(--success-dim);
  border: 1px solid #166534;
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 2rem 0 0;
}
.deliverable-box h4 {
  color: var(--success);
  margin: 0 0 0.75rem;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.deliverable-box ul { margin: 0; list-style: none; padding: 0; }
.deliverable-box li {
  padding: 0.3rem 0;
  padding-left: 1.5rem;
  position: relative;
  color: var(--text-muted);
  font-size: 0.9rem;
}
.deliverable-box li::before { content: '→'; position: absolute; left: 0; color: var(--success); }

/* ── Verification Box ── */
.verify-box {
  background: #1a1e30;
  border: 1px solid #2d4a7a;
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 1rem 0 0;
}
.verify-box h4 {
  color: #60a5fa;
  margin: 0 0 0.75rem;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.verify-box ul { margin: 0; list-style: none; padding: 0; }
.verify-box li {
  padding: 0.35rem 0;
  padding-left: 1.75rem;
  position: relative;
  font-size: 0.9rem;
  color: var(--text-muted);
}
.verify-box li::before { content: '◉'; position: absolute; left: 0; color: #60a5fa; font-size: 0.7rem; top: 0.45rem; }
.done-when {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  background: var(--code-bg);
  border-radius: 6px;
  font-size: 0.88rem;
  color: #60a5fa;
}
.done-when strong { color: #fff; }

/* ── Quiz ── */
.quiz-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  margin: 3rem 0 2rem;
  overflow: hidden;
}
.quiz-header {
  background: linear-gradient(90deg, #1a2a1a, #1a1d27);
  border-bottom: 1px solid var(--border);
  padding: 1.5rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}
.quiz-badge {
  background: var(--success);
  color: #000;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
}
.quiz-header h2 { margin: 0; font-size: 1.3rem; color: #fff; }
.quiz-score-display {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}
.quiz-body { padding: 2rem; }
.quiz-question {
  margin-bottom: 2rem;
  padding: 1.5rem;
  background: var(--surface2);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.q-number {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--success);
  margin-bottom: 0.5rem;
}
.q-text { font-size: 1rem; font-weight: 500; color: #fff; margin-bottom: 1rem; }
.q-options { display: flex; flex-direction: column; gap: 0.5rem; }
.q-option {
  padding: 0.75rem 1rem;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--text-muted);
  transition: all 0.2s;
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}
.q-option:hover:not(.answered) { border-color: var(--accent); color: var(--text); background: var(--surface2); }
.q-option .opt-letter {
  font-weight: 700;
  color: var(--accent);
  min-width: 1.2rem;
  font-size: 0.8rem;
  margin-top: 0.1rem;
}
.q-option.correct  { border-color: var(--success); background: var(--success-dim); color: var(--success); }
.q-option.wrong    { border-color: var(--danger);  background: var(--danger-dim);  color: var(--danger);  }
.q-option.reveal   { border-color: var(--success); background: var(--success-dim); color: var(--success); opacity: 0.7; }
.q-option.correct .opt-letter { color: var(--success); }
.q-option.wrong    .opt-letter { color: var(--danger);  }
.q-option.reveal   .opt-letter { color: var(--success); }
.q-explanation {
  margin-top: 0.75rem;
  padding: 0.75rem 1rem;
  background: var(--code-bg);
  border-radius: 6px;
  font-size: 0.875rem;
  color: var(--text-muted);
  display: none;
}
.q-explanation.visible { display: block; }
.q-explanation strong { color: var(--success); }
.quiz-result {
  text-align: center;
  padding: 2rem;
  display: none;
}
.quiz-result.visible { display: block; }
.result-score { font-size: 3rem; font-weight: 700; color: var(--success); }
.result-label { color: var(--text-muted); margin-top: 0.25rem; }
.result-message { margin-top: 1rem; font-size: 1rem; }
.btn-restart {
  margin-top: 1.5rem;
  padding: 0.75rem 2rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.btn-restart:hover { background: var(--accent-dim); }

/* ── Module Navigation ── */
.module-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}
.nav-btn {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  transition: all 0.2s;
  flex: 1;
  min-width: 200px;
  max-width: 300px;
}
.nav-btn:hover { border-color: var(--accent); background: var(--surface2); text-decoration: none; }
.nav-btn.prev { flex-direction: row; }
.nav-btn.next { flex-direction: row-reverse; margin-left: auto; }
.nav-btn-icon { font-size: 1.3rem; color: var(--accent); }
.nav-btn-text { flex: 1; }
.nav-btn-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-dim); font-weight: 600; }
.nav-btn-title { font-size: 0.9rem; font-weight: 600; color: #fff; }
.nav-btn.next .nav-btn-text { text-align: right; }

/* ── Hero Section (index) ── */
.hero {
  padding: 5rem 2rem 4rem;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}
.hero-eyebrow {
  display: inline-block;
  background: var(--accent-glow);
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 20px;
  padding: 0.3rem 1rem;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1.5rem;
}
.hero h1 { font-size: 3rem; line-height: 1.15; margin-bottom: 1.25rem; }
.hero h1 span { color: var(--accent); }
.hero-sub { font-size: 1.15rem; color: var(--text-muted); max-width: 600px; margin: 0 auto 2.5rem; }
.cta-group { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent);
  color: #fff;
  padding: 0.85rem 2rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: background 0.2s;
}
.btn-primary:hover { background: var(--accent-dim); text-decoration: none; color: #fff; }
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--surface);
  color: var(--text);
  padding: 0.85rem 2rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid var(--border2);
  text-decoration: none;
  transition: all 0.2s;
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }

/* ── Module Grid (index) ── */
.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
  margin: 2rem 0;
}
.module-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  text-decoration: none;
  transition: all 0.2s;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  position: relative;
  overflow: hidden;
}
.module-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--mod-color, var(--accent));
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}
.module-card:hover { border-color: var(--border2); transform: translateY(-2px); box-shadow: var(--shadow); text-decoration: none; }
.mc-num {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--mod-color, var(--accent));
}
.mc-title { font-size: 1rem; font-weight: 600; color: #fff; }
.mc-topic { font-size: 0.82rem; color: var(--text-muted); }
.mc-arrow { margin-top: auto; color: var(--text-dim); font-size: 0.85rem; }

/* ── Instructor Section ── */
.instructor-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 3rem;
  margin: 3rem 0;
  display: flex;
  gap: 3rem;
  align-items: flex-start;
  flex-wrap: wrap;
}
.instructor-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-dim));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  font-weight: 700;
  color: #fff;
  flex-shrink: 0;
  border: 3px solid var(--border2);
}
.instructor-body { flex: 1; min-width: 250px; }
.instructor-body h2 { margin-top: 0; }
.instructor-body .title { color: var(--accent); font-size: 0.9rem; font-weight: 600; margin-bottom: 1rem; }
.tag-list { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 1.25rem; }
.tag {
  background: var(--surface2);
  border: 1px solid var(--border2);
  color: var(--text-muted);
  font-size: 0.78rem;
  padding: 0.2rem 0.7rem;
  border-radius: 20px;
}

/* ── Checklist ── */
.checklist { list-style: none; padding: 0; margin: 1rem 0; }
.checklist li {
  padding: 0.45rem 0;
  padding-left: 2rem;
  position: relative;
  color: var(--text-muted);
  font-size: 0.95rem;
}
.checklist li::before {
  content: '☐';
  position: absolute;
  left: 0;
  color: var(--border2);
  font-size: 1rem;
}

/* ── Stats Bar ── */
.stats-bar {
  display: flex;
  gap: 2rem;
  flex-wrap: wrap;
  margin: 2rem 0;
}
.stat {
  text-align: center;
  padding: 1.25rem 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  flex: 1;
  min-width: 140px;
}
.stat-value { font-size: 1.8rem; font-weight: 700; color: var(--accent); display: block; }
.stat-label { font-size: 0.78rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.06em; }

/* ── Section Heading ── */
.section-heading {
  font-size: 1.6rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 0.5rem;
}
.section-sub {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 2rem;
}

/* ── Footer ── */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.82rem;
}
footer a { color: var(--text-muted); }
footer a:hover { color: var(--accent); }

/* ── Breadcrumb ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  font-size: 0.82rem;
  color: var(--text-dim);
}
.breadcrumb a { color: var(--text-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb span { color: var(--text-dim); }

/* ── Progress Bar ── */
.progress-indicator {
  display: flex;
  gap: 3px;
  margin-bottom: 2rem;
  align-items: center;
}
.prog-dot {
  height: 4px;
  border-radius: 2px;
  background: var(--border);
  flex: 1;
  transition: background 0.3s;
}
.prog-dot.done  { background: var(--success); }
.prog-dot.current { background: var(--accent); }

/* ── Responsive ── */
@media (max-width: 768px) {
  .page-wrap { padding: 1.5rem 1rem 4rem; }
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.4rem; }
  .hero h1 { font-size: 2rem; }
  .navbar { padding: 0 1rem; }
  .instructor-section { padding: 1.5rem; gap: 1.5rem; }
  .lab-body { padding: 1.25rem; }
  .quiz-body { padding: 1.25rem; }
  .module-nav { flex-direction: column; }
  .nav-btn { max-width: 100%; }
  .nav-btn.next { margin-left: 0; }
  .module-grid { grid-template-columns: 1fr; }
}