/* ===== DARK ACADEMIC ECONOMICS SITE ===== */

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

:root {
  --bg-deep: #f8f6f2;
  --bg-card: #ffffff;
  --bg-card-hover: #f0ede8;
  --bg-surface: #eae7e0;
  --accent: #c9a84c;
  --accent-dim: #b89638;
  --accent-glow: rgba(201,168,76,.12);
  --coral: #d4705c;
  --coral-glow: rgba(212,112,92,.12);
  --teal: #4a8fa0;
  --teal-glow: rgba(74,143,160,.12);
  --text: #2a2a2a;
  --text-muted: #6b6b6b;
  --text-heading: #1a1a1a;
  --border: #d8d5ce;
  --success: #4a9a4a;
  --danger: #c44a47;
  --info: #4a8fa0;
  --radius: 10px;
  --transition: .25s ease;
  --font-body: 'Libre Baskerville', 'Georgia', serif;
  --font-heading: 'Playfair Display', 'Georgia', serif;
  --font-mono: 'Fira Code', 'Courier New', monospace;
  --max-width: 1140px;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg-deep);
  color: var(--text);
  line-height: 1.75;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* --- Typography --- */
h1, h2, h3, h4 { font-family: var(--font-heading); color: var(--text-heading); font-weight: 700; line-height: 1.25; }
h1 { font-size: 2.5rem; margin-bottom: 1rem; }
h2 { font-size: 1.8rem; margin-bottom: .75rem; }
h3 { font-size: 1.35rem; margin-bottom: .5rem; }
h4 { font-size: 1.1rem; }
p  { margin-bottom: 1rem; }
a  { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: #E8836B; }

/* --- Layout --- */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; width: 100%; }

/* --- Header / Navbar --- */
.navbar {
  background: #eae7e0;
  border-bottom: 2px solid var(--border);
  padding: .75rem 0;
  position: sticky; top: 0; z-index: 100;
  backdrop-filter: blur(12px);
}
.navbar .container { display: flex; align-items: center; justify-content: space-between; }
.nav-brand {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  color: var(--accent);
  font-weight: 700;
  letter-spacing: .5px;
  display: flex;
  align-items: center;
  gap: .6rem;
}
.nav-brand img { height: 32px; width: auto; border-radius: 4px; }
.nav-brand span { color: var(--text-muted); font-weight: 400; font-size: .85rem; margin-left: .4rem; }
.nav-links { display: flex; gap: 1.5rem; align-items: center; list-style: none; }
.nav-links a { color: var(--text-muted); font-size: .9rem; padding: .35rem 0; border-bottom: 2px solid transparent; transition: all var(--transition); }
.nav-links a:hover, .nav-links a.active { color: var(--accent); border-bottom-color: var(--accent); }

/* Mobile menu */
.nav-toggle { display: none; background: none; border: none; color: var(--text); font-size: 1.5rem; cursor: pointer; }

/* --- Hero --- */
.hero {
  text-align: center;
  padding: 5rem 1.5rem 4rem;
  background: linear-gradient(180deg, var(--bg-surface) 0%, var(--bg-deep) 100%);
  border-bottom: 1px solid var(--border);
}
.hero .hero-logo { height: 80px; margin-bottom: 1.5rem; border-radius: 8px; }
.hero h1 { font-size: 3rem; margin-bottom: .5rem; }
.hero .subtitle { font-size: 1.15rem; color: var(--text-muted); max-width: 600px; margin: 0 auto 2rem; }

/* --- Cards Grid --- */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--coral), var(--accent), var(--teal));
  opacity: 0;
  transition: opacity var(--transition);
}
.card:hover { background: var(--bg-card-hover); transform: translateY(-3px); box-shadow: 0 8px 30px rgba(0,0,0,.3); }
.card:hover::before { opacity: 1; }
.card-icon { font-size: 2.2rem; margin-bottom: 1rem; }
.card h3 { margin-bottom: .5rem; }
.card p { color: var(--text-muted); font-size: .92rem; margin-bottom: 1.25rem; }

/* --- Buttons --- */
.btn {
  display: inline-flex; align-items: center; gap: .4rem;
  padding: .65rem 1.5rem;
  border-radius: var(--radius);
  font-family: var(--font-body);
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
}
.btn-primary { background: var(--coral); color: #fff; }
.btn-primary:hover { background: #d6745c; color: #fff; transform: translateY(-1px); }
.btn-outline { background: transparent; border: 1px solid var(--accent); color: var(--accent); }
.btn-outline:hover { background: var(--accent-glow); }
.btn-sm { padding: .45rem 1rem; font-size: .82rem; }
.btn-success { background: var(--success); color: #fff; }
.btn-danger  { background: var(--danger);  color: #fff; }

/* --- Section --- */
.section { padding: 3.5rem 0; }
.section-header { text-align: center; margin-bottom: 2.5rem; }
.section-header p { color: var(--text-muted); max-width: 550px; margin: .5rem auto 0; }

/* --- Breadcrumb --- */
.breadcrumb { padding: 1rem 0; font-size: .85rem; color: var(--text-muted); }
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { margin: 0 .4rem; }

/* --- Tabs --- */
.tabs { display: flex; gap: .5rem; margin-bottom: 2rem; flex-wrap: wrap; }
.tab-btn {
  padding: .55rem 1.2rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  font-family: var(--font-body);
  font-size: .88rem;
  cursor: pointer;
  transition: all var(--transition);
}
.tab-btn.active, .tab-btn:hover { background: var(--accent-glow); color: var(--accent); border-color: var(--accent); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* --- Quiz Styles --- */
.quiz-container {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 2rem;
}
.quiz-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1.5rem; flex-wrap: wrap; gap: .5rem; }
.quiz-progress { font-size: .85rem; color: var(--text-muted); }
.quiz-score { font-size: .95rem; font-weight: 600; color: var(--accent); }

/* Diagram area */
.diagram-area {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  text-align: center;
  position: relative;
  min-height: 350px;
}
.diagram-area svg { max-width: 100%; height: auto; }

/* MCQ options */
.mcq-options { display: flex; flex-direction: column; gap: .75rem; margin: 1.5rem 0; }
.mcq-option {
  display: flex; align-items: center; gap: .75rem;
  padding: 1rem 1.25rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  font-size: .95rem;
  color: #f5f3ed;
  font-weight: 500;
}
.mcq-option:hover { border-color: var(--accent); background: var(--accent-glow); }
.mcq-option.selected { border-color: var(--accent); background: var(--accent-glow); }
.mcq-option.correct { border-color: var(--success); background: rgba(92,184,92,.12); color: #f5f3ed; }
.mcq-option.incorrect { border-color: var(--danger); background: rgba(217,83,79,.12); color: #f5f3ed; }
.mcq-option .letter {
  width: 28px; height: 28px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg-card); border: 1px solid var(--border);
  font-size: .8rem; font-weight: 600; flex-shrink: 0;
}
.mcq-option.correct .letter { background: var(--success); color: #fff; border-color: var(--success); }
.mcq-option.incorrect .letter { background: var(--danger); color: #fff; border-color: var(--danger); }

/* Label quiz */
.label-input {
  padding: .45rem .75rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-family: var(--font-body);
  font-size: .85rem;
  width: 130px;
  text-align: center;
  transition: border-color var(--transition);
}
.label-input:focus { outline: none; border-color: var(--accent); }
.label-input.correct { border-color: var(--success); background: rgba(92,184,92,.08); }
.label-input.incorrect { border-color: var(--danger); background: rgba(217,83,79,.08); }

/* Explanation box */
.explanation {
  background: var(--accent-glow);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1.25rem;
  margin-top: 1rem;
  font-size: .92rem;
  display: none;
}
.explanation.show { display: block; }
.explanation h4 { color: var(--accent); margin-bottom: .35rem; }

/* --- Analysis / Evaluation Practice --- */
.practice-prompt {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 1.5rem;
}
.practice-prompt .prompt-label {
  font-size: .75rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--accent);
  margin-bottom: .5rem;
}
.practice-prompt .question-text { font-size: 1.05rem; line-height: 1.7; }
.marks-badge {
  display: inline-block;
  background: var(--accent-glow);
  color: var(--accent);
  padding: .2rem .65rem;
  border-radius: 20px;
  font-size: .78rem;
  font-weight: 600;
  margin-top: .5rem;
}

.writing-area {
  width: 100%;
  min-height: 200px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: var(--font-body);
  font-size: .95rem;
  padding: 1.25rem;
  line-height: 1.7;
  resize: vertical;
  transition: border-color var(--transition);
}
.writing-area:focus { outline: none; border-color: var(--accent); }

.model-answer-toggle {
  margin-top: 1rem;
}
.model-answer {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-top: 1rem;
  display: none;
  line-height: 1.8;
}
.model-answer.show { display: block; animation: fadeIn .3s ease; }
.model-answer h4 { color: var(--accent); margin-bottom: .75rem; }
.model-answer .chain { margin-bottom: 1rem; }
.model-answer .chain-step {
  padding-left: 1.25rem;
  border-left: 2px solid var(--accent-dim);
  margin-bottom: .75rem;
}
.model-answer .eval-point {
  padding: .75rem 1rem;
  background: var(--bg-surface);
  border-radius: var(--radius);
  margin-bottom: .5rem;
  border-left: 3px solid var(--info);
}

/* --- Model Answers (Past Papers) --- */
.paper-list { display: flex; flex-direction: column; gap: 1rem; }
.paper-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.paper-header {
  padding: 1.25rem 1.5rem;
  display: flex; justify-content: space-between; align-items: center;
  cursor: pointer;
  transition: background var(--transition);
}
.paper-header:hover { background: var(--bg-card-hover); }
.paper-header h4 { flex: 1; }
.paper-header .arrow { font-size: 1.2rem; color: var(--text-muted); transition: transform var(--transition); }
.paper-item.open .paper-header .arrow { transform: rotate(180deg); }
.paper-body { padding: 0 1.5rem; max-height: 0; overflow: hidden; transition: all .4s ease; }
.paper-item.open .paper-body { max-height: 5000px; padding: 1rem 1.5rem 1.5rem; }
.answer-section { margin-bottom: 1.5rem; }
.answer-section:last-child { margin-bottom: 0; }

/* --- Tags --- */
.tag {
  display: inline-block;
  padding: .15rem .6rem;
  border-radius: 20px;
  font-size: .72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .5px;
}
.tag-micro  { background: rgba(91,192,222,.15); color: var(--info); }
.tag-macro  { background: rgba(92,184,92,.15); color: var(--success); }
.tag-hl     { background: rgba(201,168,76,.15); color: var(--accent); }
.tag-sl     { background: rgba(155,89,182,.15); color: #bb8fce; }

/* --- Topic List --- */
.topic-list { list-style: none; }
.topic-list li {
  padding: .85rem 1.25rem;
  border-bottom: 1px solid var(--border);
  display: flex; justify-content: space-between; align-items: center;
  transition: background var(--transition);
}
.topic-list li:hover { background: var(--bg-card-hover); }
.topic-list li:last-child { border-bottom: none; }

/* --- Footer --- */
.footer {
  margin-top: auto;
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  font-size: .85rem;
  color: var(--text-muted);
}

/* --- Utility --- */
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.mt-1 { margin-top: .5rem; } .mt-2 { margin-top: 1rem; } .mt-3 { margin-top: 1.5rem; } .mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: .5rem; } .mb-2 { margin-bottom: 1rem; } .mb-3 { margin-bottom: 1.5rem; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.gap-1 { gap: .5rem; } .gap-2 { gap: 1rem; }

/* --- Animations --- */
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
.fade-in { animation: fadeIn .4s ease; }

/* --- AO Colour System for Essay Practice --- */
:root {
  --ao1: #5bc0de;   /* Knowledge — blue */
  --ao2: #5cb85c;   /* Application — green */
  --ao3: #c9a84c;   /* Analysis — gold */
  --ao4: #bb8fce;   /* Evaluation — purple */
  --ao1-bg: rgba(91,192,222,.12);
  --ao2-bg: rgba(92,184,92,.12);
  --ao3-bg: rgba(201,168,76,.12);
  --ao4-bg: rgba(187,143,206,.12);
}

.ao-legend {
  display: flex; flex-wrap: wrap; gap: 1rem;
  padding: 1.25rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 2rem;
  font-size: .88rem;
}
.ao-legend-item { display: flex; align-items: center; gap: .4rem; }
.ao-legend-dot {
  width: 14px; height: 14px; border-radius: 3px; flex-shrink: 0;
}
.ao-legend-dot.ao1 { background: var(--ao1); }
.ao-legend-dot.ao2 { background: var(--ao2); }
.ao-legend-dot.ao3 { background: var(--ao3); }
.ao-legend-dot.ao4 { background: var(--ao4); }

/* AO input sections */
.ao-inputs { display: flex; flex-direction: column; gap: 1rem; margin-bottom: 1.5rem; }
.ao-input-group { position: relative; }
.ao-input-label {
  display: inline-block;
  font-size: .75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: .2rem .6rem;
  border-radius: 4px;
  margin-bottom: .4rem;
}
.ao-input-label.ao1 { background: var(--ao1-bg); color: var(--ao1); }
.ao-input-label.ao2 { background: var(--ao2-bg); color: var(--ao2); }
.ao-input-label.ao3 { background: var(--ao3-bg); color: var(--ao3); }
.ao-input-label.ao4 { background: var(--ao4-bg); color: var(--ao4); }

.ao-textarea {
  width: 100%;
  min-height: 120px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: var(--font-body);
  font-size: .92rem;
  padding: 1rem 1.25rem;
  line-height: 1.7;
  resize: vertical;
  transition: border-color var(--transition);
}
.ao-textarea:focus { outline: none; }
.ao-textarea.ao1-border:focus { border-color: var(--ao1); }
.ao-textarea.ao2-border:focus { border-color: var(--ao2); }
.ao-textarea.ao3-border:focus { border-color: var(--ao3); }
.ao-textarea.ao4-border:focus { border-color: var(--ao4); }

/* Colour-coded model essay paragraphs */
.model-essay { line-height: 1.85; }
.model-essay .ao-para {
  padding: .85rem 1.15rem;
  border-radius: var(--radius);
  margin-bottom: .75rem;
  border-left: 4px solid;
  font-size: .93rem;
}
.model-essay .ao-para.ao1 { background: var(--ao1-bg); border-color: var(--ao1); }
.model-essay .ao-para.ao2 { background: var(--ao2-bg); border-color: var(--ao2); }
.model-essay .ao-para.ao3 { background: var(--ao3-bg); border-color: var(--ao3); }
.model-essay .ao-para.ao4 { background: var(--ao4-bg); border-color: var(--ao4); }
.model-essay .ao-para .ao-tag {
  display: inline-block;
  font-size: .68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .8px;
  padding: .1rem .45rem;
  border-radius: 3px;
  margin-bottom: .35rem;
}
.model-essay .ao-para.ao1 .ao-tag { background: var(--ao1); color: var(--bg-deep); }
.model-essay .ao-para.ao2 .ao-tag { background: var(--ao2); color: var(--bg-deep); }
.model-essay .ao-para.ao3 .ao-tag { background: var(--ao3); color: var(--bg-deep); }
.model-essay .ao-para.ao4 .ao-tag { background: var(--ao4); color: var(--bg-deep); }

/* --- Level Select (MCQ) --- */
.level-select { }
.level-header { margin-bottom: 1.5rem; }
.level-header h3 { margin-bottom: .35rem; }
.level-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}
.level-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  text-align: center;
}
.level-card:hover { border-color: var(--accent); background: var(--bg-card-hover); transform: translateY(-2px); box-shadow: 0 6px 20px rgba(0,0,0,.25); }
.level-card.level-complete { border-color: var(--success); }
.level-card.level-attempted { border-color: var(--coral); }
.level-card.level-gold { border-color: var(--accent); background: rgba(232,197,90,.06); }
.level-number {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: .25rem;
}
.level-name {
  font-size: .78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--accent);
  margin-bottom: .5rem;
}
.level-desc {
  font-size: .8rem;
  color: var(--text-muted);
  margin-bottom: .75rem;
  line-height: 1.4;
}
.level-status {
  font-size: .75rem;
  color: var(--text-muted);
  padding-top: .5rem;
  border-top: 1px solid var(--border);
}
.level-badge {
  position: absolute;
  top: .5rem; right: .5rem;
  color: var(--accent);
  font-size: 1.1rem;
}
.quiz-level-badge {
  display: inline-block;
  padding: .2rem .65rem;
  border-radius: 20px;
  font-size: .72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .5px;
}
.level-badge-1 { background: rgba(92,184,92,.15); color: var(--success); }
.level-badge-2 { background: rgba(91,192,222,.15); color: var(--info); }
.level-badge-3 { background: rgba(232,197,90,.15); color: var(--accent); }
.level-badge-4 { background: rgba(232,131,107,.15); color: var(--coral); }
.level-badge-5 { background: rgba(187,143,206,.15); color: #bb8fce; }

/* --- Profile System --- */
.profile-form {
  max-width: 420px;
  margin: 0 auto;
}
.form-group {
  margin-bottom: 1.25rem;
}
.form-group label {
  display: block;
  font-size: .82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .8px;
  color: var(--text-muted);
  margin-bottom: .4rem;
}
.form-input, .form-select {
  width: 100%;
  padding: .7rem 1rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: var(--font-body);
  font-size: .92rem;
  transition: border-color var(--transition);
}
.form-input:focus, .form-select:focus { outline: none; border-color: var(--accent); }
.form-select option { background: var(--bg-card); }
.form-error {
  color: var(--danger);
  font-size: .82rem;
  margin-top: .35rem;
  display: none;
}
.form-error.show { display: block; }

.profile-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 1.5rem;
}
.profile-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}
.stat-box {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-align: center;
}
.stat-box .stat-val {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}
.stat-box .stat-label {
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-top: .35rem;
}
.progress-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .88rem;
}
.progress-table th {
  text-align: left;
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  padding: .6rem .75rem;
  border-bottom: 1px solid var(--border);
}
.progress-table td {
  padding: .6rem .75rem;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
.progress-bar-bg {
  background: var(--bg-surface);
  border-radius: 4px;
  height: 8px;
  overflow: hidden;
  width: 100%;
}
.progress-bar-fill {
  height: 100%;
  border-radius: 4px;
  background: linear-gradient(90deg, var(--coral), var(--accent));
  transition: width .4s ease;
}
.tab-toggle {
  display: flex; gap: 0; margin-bottom: 1.5rem;
}
.tab-toggle button {
  flex: 1;
  padding: .65rem 1rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-family: var(--font-body);
  font-size: .85rem;
  cursor: pointer;
  transition: all var(--transition);
}
.tab-toggle button:first-child { border-radius: var(--radius) 0 0 var(--radius); }
.tab-toggle button:last-child { border-radius: 0 var(--radius) var(--radius) 0; }
.tab-toggle button.active { background: var(--accent-glow); color: var(--accent); border-color: var(--accent); }

/* --- Responsive --- */
@media (max-width: 768px) {
  .nav-links { display: none; flex-direction: column; position: absolute; top: 100%; left: 0; right: 0; background: var(--bg-surface); border-bottom: 1px solid var(--border); padding: 1rem; }
  .nav-links.open { display: flex; }
  .nav-toggle { display: block; }
  .hero h1 { font-size: 2rem; }
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.4rem; }
  .cards-grid { grid-template-columns: 1fr; }
  .quiz-container { padding: 1.25rem; }
  .diagram-area { min-height: 250px; padding: 1rem; }
}