/* ===== Variables ===== */
:root {
  --primary: #1a3a5c;
  --primary-light: #2471a3;
  --accent: #c0392b;
  --success: #27ae60;
  --danger: #e74c3c;
  --bg: #f0f4f8;
  --card: #ffffff;
  --text: #2c3e50;
  --text-muted: #7f8c8d;
  --border: #dce1e7;
  --shadow: 0 4px 20px rgba(0,0,0,0.1);
  --radius: 12px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: 'Sarabun', 'Segoe UI', sans-serif; background: var(--bg); color: var(--text); font-size: 16px; line-height: 1.6; }
.container { max-width: 960px; margin: 0 auto; padding: 0 20px; }
.container-sm { max-width: 480px; margin: 0 auto; padding: 0 20px; }
.container-lg { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* Navbar */
.navbar { background: var(--primary); color: #fff; padding: 0 24px; height: 60px; display: flex; align-items: center; justify-content: space-between; box-shadow: 0 2px 8px rgba(0,0,0,0.2); position: sticky; top: 0; z-index: 100; }
.navbar-brand { font-size: 1.15rem; font-weight: 700; }
.navbar-brand span { color: #f4d03f; }
.navbar-right { display: flex; align-items: center; gap: 16px; }
.navbar-user { font-size: 0.9rem; opacity: 0.9; }
.btn-logout { background: rgba(255,255,255,0.15); color: #fff; border: 1px solid rgba(255,255,255,0.3); padding: 6px 14px; border-radius: 6px; cursor: pointer; font-size: 0.85rem; transition: background 0.2s; }
.btn-logout:hover { background: rgba(255,255,255,0.25); }

/* Cards */
.card { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 32px; }
.card-sm { padding: 24px; }

/* Buttons */
.btn { display: inline-block; padding: 10px 24px; border-radius: 8px; font-size: 1rem; font-weight: 600; cursor: pointer; transition: all 0.2s; border: none; text-align: center; text-decoration: none; font-family: inherit; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-light); }
.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: #a93226; }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-outline { background: transparent; border: 2px solid var(--primary); color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: #fff; }
.count-btn.active { background: var(--primary); color: #fff; }
.btn-lg { padding: 14px 32px; font-size: 1.1rem; }
.btn-block { display: block; width: 100%; }
.btn-sm { padding: 6px 14px; font-size: 0.88rem; }

/* Forms */
.form-group { margin-bottom: 20px; }
.form-label { display: block; font-weight: 600; margin-bottom: 6px; font-size: 0.95rem; }
.form-control { width: 100%; padding: 10px 14px; border: 2px solid var(--border); border-radius: 8px; font-size: 1rem; transition: border-color 0.2s; font-family: inherit; }
.form-control:focus { outline: none; border-color: var(--primary); }

/* Login */
.login-page { min-height: 100vh; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, #1a3a5c 0%, #2c5f8a 100%); padding: 20px; }
.login-box { background: #fff; border-radius: 16px; box-shadow: 0 8px 40px rgba(0,0,0,0.2); padding: 48px 40px; width: 100%; max-width: 440px; }
.login-logo { text-align: center; margin-bottom: 32px; }
.login-logo-icon { width: 80px; height: 80px; background: var(--primary); border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; font-size: 2.2rem; margin-bottom: 16px; }
.login-logo h1 { font-size: 1.3rem; color: var(--primary); font-weight: 700; }
.login-logo p { font-size: 0.9rem; color: var(--text-muted); margin-top: 4px; }
.login-error { background: #fdecea; color: var(--danger); border: 1px solid #f5c6cb; border-radius: 8px; padding: 10px 14px; font-size: 0.9rem; margin-bottom: 16px; display: none; }

/* Dashboard */
.dashboard-hero { background: linear-gradient(135deg, var(--primary) 0%, #2c5f8a 100%); color: #fff; padding: 40px 0; margin-bottom: 32px; }
.dashboard-hero h2 { font-size: 1.8rem; margin-bottom: 8px; }
.dashboard-hero p { opacity: 0.85; }
.stats-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 16px; margin-bottom: 32px; }
.stat-card { background: #fff; border-radius: 12px; padding: 20px; text-align: center; box-shadow: var(--shadow); }
.stat-card .stat-num { font-size: 2rem; font-weight: 700; color: var(--primary); }
.stat-card .stat-label { font-size: 0.85rem; color: var(--text-muted); margin-top: 4px; }

.exam-set-card { background: #fff; border-radius: var(--radius); box-shadow: var(--shadow); padding: 24px; cursor: pointer; transition: transform 0.2s, box-shadow 0.2s; border: 2px solid transparent; position: relative; }
.exam-set-card:hover { transform: translateY(-3px); box-shadow: 0 8px 30px rgba(0,0,0,0.15); }
.exam-set-card.passed { border-color: var(--success); }
.exam-set-card.failed { border-color: var(--danger); }
.exam-set-num { font-size: 2.5rem; font-weight: 700; color: var(--primary); line-height: 1; }
.exam-set-title { font-weight: 600; margin: 8px 0 4px; }
.exam-set-meta { font-size: 0.82rem; color: var(--text-muted); }
.status-badge { position: absolute; top: 16px; right: 16px; background: var(--text-muted); color: #fff; font-size: 0.75rem; padding: 3px 10px; border-radius: 20px; font-weight: 600; }
.exam-set-card.passed .status-badge { background: var(--success); }
.exam-set-card.failed .status-badge { background: var(--danger); }
.exam-sets-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px; margin-top: 24px; }

/* Exam */
.exam-header { background: var(--primary); color: #fff; padding: 16px 24px; display: flex; align-items: center; justify-content: space-between; position: sticky; top: 0; z-index: 100; }
.exam-header h3 { font-size: 1rem; }
.exam-timer { background: rgba(255,255,255,0.15); padding: 6px 16px; border-radius: 20px; font-size: 1.1rem; font-weight: 700; font-variant-numeric: tabular-nums; letter-spacing: 1px; }
.exam-timer.warning { background: #e67e22; }
.exam-timer.danger { background: var(--danger); animation: pulse 1s infinite; }
@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: 0.7; } }
.exam-progress-bar { height: 4px; background: rgba(255,255,255,0.2); }
.exam-progress-fill { height: 100%; background: #f4d03f; transition: width 0.3s; }
.exam-body { padding: 24px; max-width: 860px; margin: 0 auto; }
.question-block { margin-bottom: 32px; background: #fff; border-radius: 12px; padding: 20px; box-shadow: 0 2px 8px rgba(0,0,0,0.07); }
.question-num { font-size: 0.8rem; color: var(--text-muted); font-weight: 600; margin-bottom: 8px; }
.question-subject-badge { display: inline-block; background: #ebf5fb; color: var(--primary); font-size: 0.75rem; padding: 2px 8px; border-radius: 10px; font-weight: 600; margin-bottom: 8px; }
.question-text { font-size: 1.05rem; font-weight: 600; margin-bottom: 16px; line-height: 1.7; }
.choices { display: flex; flex-direction: column; gap: 10px; }
.choice-label { display: flex; align-items: flex-start; gap: 12px; padding: 12px 16px; border: 2px solid var(--border); border-radius: 8px; cursor: pointer; transition: all 0.15s; }
.choice-label:hover { border-color: var(--primary); background: #f0f4f8; }
.choice-label.selected { border-color: var(--primary); background: #ebf5fb; }
.choice-label input[type="radio"] { margin-top: 3px; accent-color: var(--primary); flex-shrink: 0; }
.choice-letter { font-weight: 700; color: var(--primary); flex-shrink: 0; min-width: 20px; }

.exam-nav { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; padding: 10px 24px; background: #fff; border-top: 1px solid var(--border); position: sticky; bottom: 0; gap: 8px; }
.exam-nav.collapsed .question-dots { display: none; }
.nav-toggle-btn { width: 100%; background: none; border: none; color: var(--text-muted); font-size: 0.75rem; cursor: pointer; padding: 0 0 4px; text-align: center; order: -1; }
.question-dots { display: flex; flex-wrap: wrap; gap: 6px; max-width: 600px; }
.q-dot { width: 28px; height: 28px; border-radius: 50%; background: var(--border); display: flex; align-items: center; justify-content: center; font-size: 0.7rem; font-weight: 600; cursor: pointer; transition: background 0.15s; color: var(--text-muted); }
.q-dot.answered { background: var(--primary); color: #fff; }

/* Modal */
.modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.5); z-index: 200; display: flex; align-items: center; justify-content: center; }
.modal-box { background: #fff; border-radius: var(--radius); padding: 32px; max-width: 440px; width: 90%; text-align: center; box-shadow: 0 12px 48px rgba(0,0,0,0.2); }
.modal-box h3 { font-size: 1.3rem; margin-bottom: 12px; }
.modal-box p { color: var(--text-muted); margin-bottom: 24px; }
.modal-actions { display: flex; gap: 12px; justify-content: center; }

/* Result */
.result-hero { text-align: center; padding: 48px 24px; }
.result-circle { width: 140px; height: 140px; border-radius: 50%; margin: 0 auto 24px; display: flex; flex-direction: column; align-items: center; justify-content: center; font-size: 2.5rem; font-weight: 700; color: #fff; }
.result-circle.pass { background: var(--success); }
.result-circle.fail { background: var(--danger); }
.result-circle .result-label { font-size: 0.75rem; font-weight: 600; opacity: 0.9; }
.result-verdict { font-size: 1.8rem; font-weight: 700; margin-bottom: 8px; }
.result-verdict.pass { color: var(--success); }
.result-verdict.fail { color: var(--danger); }
.result-detail { color: var(--text-muted); }
.result-breakdown { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 16px; margin: 24px 0; }
.breakdown-item { text-align: center; padding: 16px; background: var(--bg); border-radius: 10px; }
.breakdown-num { font-size: 1.6rem; font-weight: 700; color: var(--primary); }
.breakdown-label { font-size: 0.82rem; color: var(--text-muted); }

/* Subject Score */
.subject-score-row { display: flex; align-items: center; gap: 12px; padding: 12px 0; border-bottom: 1px solid var(--border); }
.subject-score-row:last-child { border-bottom: none; }
.subject-name { flex: 1; font-weight: 600; font-size: 0.9rem; }
.subject-bar-wrap { flex: 2; height: 10px; background: var(--border); border-radius: 5px; overflow: hidden; }
.subject-bar-fill { height: 100%; border-radius: 5px; background: var(--primary); transition: width 0.5s; }
.subject-score-text { font-size: 0.85rem; font-weight: 600; min-width: 60px; text-align: right; }

/* Review */
.review-item { background: var(--bg); border-radius: 10px; padding: 16px; margin-bottom: 12px; border-left: 4px solid var(--border); }
.review-item.correct { border-color: var(--success); }
.review-item.wrong { border-color: var(--danger); }
.review-q { font-weight: 600; margin-bottom: 8px; }
.review-answer { font-size: 0.88rem; }
.review-answer .user-ans { color: var(--danger); }
.review-answer .correct-ans { color: var(--success); }

/* History */
.history-table { width: 100%; border-collapse: collapse; }
.history-table th, .history-table td { padding: 12px 16px; text-align: left; border-bottom: 1px solid var(--border); font-size: 0.9rem; }
.history-table th { background: var(--bg); font-weight: 600; color: var(--text-muted); }
.badge-pass { background: #d5f5e3; color: var(--success); padding: 3px 10px; border-radius: 12px; font-size: 0.8rem; font-weight: 600; }
.badge-fail { background: #fadbd8; color: var(--danger); padding: 3px 10px; border-radius: 12px; font-size: 0.8rem; font-weight: 600; }

/* Utilities */
.section-title { font-size: 1.3rem; font-weight: 700; margin-bottom: 4px; }
.section-sub { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 24px; }
.text-center { text-align: center; }
.mt-8 { margin-top: 8px; } .mt-16 { margin-top: 16px; } .mt-24 { margin-top: 24px; } .mt-32 { margin-top: 32px; }
.mb-8 { margin-bottom: 8px; } .mb-16 { margin-bottom: 16px; } .mb-24 { margin-bottom: 24px; }
.hidden { display: none !important; }

/* Subject tab filter */
.subject-tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 24px; }
.subject-tab { padding: 6px 14px; border-radius: 20px; border: 2px solid var(--border); background: #fff; color: var(--text-muted); cursor: pointer; font-size: 0.85rem; font-weight: 600; transition: all 0.15s; font-family: inherit; }
.subject-tab.active { border-color: var(--primary); background: var(--primary); color: #fff; }

@media (max-width: 600px) {
  .login-box { padding: 32px 24px; }
  .exam-sets-grid { grid-template-columns: 1fr; }
  .navbar-brand { font-size: 0.95rem; }
  .exam-header { flex-wrap: wrap; gap: 8px; }
}