/* ============================================================
   ExamHub — Complete Stylesheet
   ============================================================ */

:root {
  --primary:       #4f46e5;
  --primary-dark:  #3730a3;
  --primary-light: #eef2ff;
  --secondary:     #06b6d4;
  --success:       #10b981;
  --danger:        #ef4444;
  --warning:       #f59e0b;
  --dark:          #0f172a;
  --gray:          #64748b;
  --light-bg:      #f8fafc;
  --border:        #e2e8f0;
  --shadow:    0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.1), 0 2px 4px -1px rgba(0,0,0,.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.1), 0 4px 6px -2px rgba(0,0,0,.05);
  --radius:    12px;
  --radius-sm: 8px;
}

/* ── Base ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
body { font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif; color: var(--dark); background: var(--light-bg); line-height: 1.6; margin: 0; }
body.lang-bn { font-family: 'Noto Sans Bengali', 'Inter', sans-serif; }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; }
main { min-height: 60vh; }

/* ── Topbar ────────────────────────────────────────── */
.topbar { background: #f1f5f9; border-bottom: 1px solid var(--border); font-size: 12px; }

/* ── Brand ─────────────────────────────────────────── */
.brand-icon {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: var(--radius-sm);
  display: inline-flex; align-items: center; justify-content: center;
  color: white; font-size: 18px; flex-shrink: 0;
}

/* ── Navbar ─────────────────────────────────────────── */
.navbar-brand { font-size: 1.2rem; color: var(--dark) !important; font-weight: 700; }
.navbar-brand:hover { color: var(--primary) !important; }
.nav-link { color: var(--gray) !important; font-weight: 500; padding: .5rem .75rem !important; border-radius: var(--radius-sm); transition: all .2s; }
.nav-link:hover, .nav-link.active { color: var(--primary) !important; background: var(--primary-light); }

/* ── Buttons ────────────────────────────────────────── */
.btn { border-radius: var(--radius-sm); font-weight: 500; }
.btn-primary { background: var(--primary); border-color: var(--primary); }
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); }
.btn-outline-primary { color: var(--primary); border-color: var(--primary); }
.btn-outline-primary:hover { background: var(--primary); border-color: var(--primary); color: white; }

/* ── Forms ──────────────────────────────────────────── */
.form-control, .form-select {
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--border);
  padding: .55rem .9rem;
  font-size: .95rem;
  transition: border-color .2s, box-shadow .2s;
}
.form-control:focus, .form-select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79,70,229,.12);
  outline: none;
}
.form-label { font-weight: 500; font-size: .9rem; color: #374151; margin-bottom: 5px; }
.input-group-text {
  background: var(--primary-light); border-color: var(--border);
  color: var(--primary); border-radius: var(--radius-sm) 0 0 var(--radius-sm) !important;
}
.form-text { font-size: .8rem; color: var(--gray); }

/* ── Cards ──────────────────────────────────────────── */
.card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  background: white;
  transition: box-shadow .2s, transform .2s;
}
.card:hover { box-shadow: var(--shadow-md); }
.card-header {
  background: #f8f9ff;
  border-bottom: 1px solid var(--border);
  font-weight: 600;
  border-radius: var(--radius) var(--radius) 0 0 !important;
}
.card-footer { border-top: 1px solid var(--border); }
.hover-lift:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }

/* ── Alerts ─────────────────────────────────────────── */
.alert { border-radius: var(--radius-sm); border: none; }
.alert-success { background: #f0fdf4; color: #166534; }
.alert-danger  { background: #fff1f2; color: #991b1b; }
.alert-warning { background: #fffbeb; color: #92400e; }
.alert-info    { background: #eff6ff; color: #1e40af; }
.alert-secondary { background: #f8fafc; color: #475569; }

/* ── Hero ───────────────────────────────────────────── */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 50%, var(--secondary) 100%);
  color: white; padding: 80px 0; position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Ccircle cx='30' cy='30' r='4'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}
.hero h1 { font-size: clamp(2rem, 5vw, 3.5rem); font-weight: 800; line-height: 1.2; }
.hero p.lead { font-size: 1.15rem; opacity: .9; }
.hero-stats {
  background: rgba(255,255,255,.15); backdrop-filter: blur(10px);
  border-radius: var(--radius); padding: 28px;
  border: 1px solid rgba(255,255,255,.2);
}

/* ── Sections ───────────────────────────────────────── */
.section-title { font-size: 1.75rem; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
.section-badge {
  display: inline-block; background: var(--primary-light); color: var(--primary);
  font-size: 11px; font-weight: 700; padding: 4px 14px; border-radius: 50px;
  text-transform: uppercase; letter-spacing: 1px; margin-bottom: 12px;
}

/* ── Course card ────────────────────────────────────── */
.course-card { border-radius: var(--radius); overflow: hidden; }
.course-card .card-img-top { height: 180px; object-fit: cover; width: 100%; }
.course-thumb {
  height: 180px; background: linear-gradient(135deg, var(--primary-light), #ddd6fe);
  display: flex; align-items: center; justify-content: center; font-size: 60px;
}
.cat-badge {
  display: inline-block; font-size: 11px; font-weight: 600; padding: 3px 10px;
  border-radius: 50px; background: var(--primary-light); color: var(--primary);
}
.price-free { color: var(--success); font-weight: 700; }
.price-paid { color: var(--primary); font-weight: 700; }

/* ── Exam card ──────────────────────────────────────── */
.exam-card .exam-meta span { font-size: 12px; color: var(--gray); }
.exam-status-free { background: #dcfce7; color: #16a34a; padding: 3px 10px; border-radius: 50px; font-size: 11px; font-weight: 600; }
.exam-status-paid { background: #fef3c7; color: #d97706; padding: 3px 10px; border-radius: 50px; font-size: 11px; font-weight: 600; }

/* ── Exam taking ────────────────────────────────────── */
.exam-header { background: var(--primary); color: white; padding: 14px 0; position: sticky; top: 0; z-index: 200; }
.exam-timer { font-size: 1.5rem; font-weight: 700; font-variant-numeric: tabular-nums; letter-spacing: 2px; }
.exam-timer.warning { color: #fcd34d; }
.exam-timer.danger  { color: #f87171; animation: timerPulse 1s infinite; }
@keyframes timerPulse { 0%,100%{opacity:1} 50%{opacity:.5} }

.question-nav .q-btn {
  width: 36px; height: 36px; font-size: 12px; font-weight: 600;
  border-radius: var(--radius-sm); border: 2px solid var(--border);
  background: white; cursor: pointer; transition: all .15s;
  display: inline-flex; align-items: center; justify-content: center;
}
.question-nav .q-btn.answered { background: var(--success); border-color: var(--success); color: white; }
.question-nav .q-btn.current  { border-color: var(--primary); color: var(--primary); font-weight: 700; }
.question-nav .q-btn.skipped  { background: var(--warning); border-color: var(--warning); color: white; }

.option-card {
  border: 2px solid var(--border); border-radius: var(--radius-sm);
  padding: 14px 18px; cursor: pointer; transition: all .15s;
  display: flex; align-items: center; gap: 12px; margin-bottom: 10px;
  background: white; user-select: none;
}
.option-card:hover   { border-color: var(--primary); background: var(--primary-light); }
.option-card.selected{ border-color: var(--primary); background: var(--primary-light); }
.option-card.correct { border-color: var(--success); background: #f0fdf4; }
.option-card.wrong   { border-color: var(--danger);  background: #fff1f2; }
.option-card input[type="radio"] { accent-color: var(--primary); width: 18px; height: 18px; flex-shrink: 0; }
.option-letter-badge {
  width: 28px; height: 28px; border-radius: 50%; background: var(--primary-light);
  color: var(--primary); font-weight: 700; font-size: 13px;
  display: inline-flex; align-items: center; justify-content: center; flex-shrink: 0;
}

/* ── Progress ───────────────────────────────────────── */
.progress-thin { height: 4px; border-radius: 50px; }

/* ── Result page ────────────────────────────────────── */
.result-circle {
  width: 150px; height: 150px; border-radius: 50%;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  font-weight: 800; margin: 0 auto;
}
.result-pass { background: linear-gradient(135deg, #dcfce7, #86efac); border: 4px solid var(--success); color: #166534; }
.result-fail { background: linear-gradient(135deg, #fff1f2, #fecaca); border: 4px solid var(--danger); color: #991b1b; }
.result-circle .big-num { font-size: 2.5rem; line-height: 1; }
.result-circle .small-text { font-size: .75rem; opacity: .8; }

/* ── Leaderboard ────────────────────────────────────── */
.leaderboard-row {
  border-radius: var(--radius-sm); padding: 12px 16px; margin-bottom: 8px;
  border: 1px solid var(--border); display: flex; align-items: center; gap: 12px; background: white;
  transition: transform .15s;
}
.leaderboard-row:hover { transform: translateX(4px); }
.leaderboard-row.top-1 { background: linear-gradient(135deg, #fef9c3, #fde047); border-color: #fbbf24; }
.leaderboard-row.top-2 { background: linear-gradient(135deg, #f1f5f9, #e2e8f0); border-color: #94a3b8; }
.leaderboard-row.top-3 { background: linear-gradient(135deg, #fff7ed, #fed7aa); border-color: #f97316; }
.rank-badge {
  width: 34px; height: 34px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 14px; flex-shrink: 0;
}

/* ── Auth pages ─────────────────────────────────────── */
.auth-wrapper {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, var(--primary-light) 0%, #ddd6fe 100%);
  padding: 20px;
}
.auth-card {
  background: white; border-radius: var(--radius); padding: 40px;
  box-shadow: var(--shadow-lg); width: 100%; max-width: 440px;
}
.auth-card .auth-logo { text-align: center; margin-bottom: 28px; }

/* ── Dashboard stats ────────────────────────────────── */
.stat-card { text-align: center; padding: 24px; }
.stat-card .stat-number {
  font-size: 2.5rem; font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.stat-card .stat-label { color: var(--gray); font-size: .9rem; font-weight: 500; }

/* ── Admin sidebar ──────────────────────────────────── */
.admin-sidebar {
  width: 260px; min-height: 100vh; background: var(--dark);
  position: fixed; top: 0; left: 0; z-index: 1000;
  transition: transform .3s; display: flex; flex-direction: column; overflow-y: auto;
}
.admin-sidebar .sidebar-brand { padding: 20px; border-bottom: 1px solid rgba(255,255,255,.1); flex-shrink: 0; }
.admin-sidebar .nav-link {
  color: rgba(255,255,255,.7) !important; padding: 10px 20px !important;
  border-radius: 0; display: flex; align-items: center; gap: 10px;
  font-size: .88rem; transition: all .2s;
}
.admin-sidebar .nav-link:hover, .admin-sidebar .nav-link.active {
  background: rgba(255,255,255,.1); color: white !important;
}
.admin-sidebar .nav-link i { width: 18px; text-align: center; }
.admin-sidebar .sidebar-section {
  padding: 10px 20px 4px; font-size: 10px; text-transform: uppercase;
  letter-spacing: 1.5px; color: rgba(255,255,255,.3); font-weight: 700; margin-top: 8px;
}
.admin-content { margin-left: 260px; min-height: 100vh; }
.admin-topbar {
  background: white; border-bottom: 1px solid var(--border);
  padding: 12px 24px; display: flex; justify-content: space-between; align-items: center;
  position: sticky; top: 0; z-index: 100; box-shadow: var(--shadow);
}
.admin-main { padding: 24px; max-width: 1400px; }

/* Admin stat widgets */
.stat-widget { border-radius: var(--radius); padding: 22px; color: white; position: relative; overflow: hidden; }
.stat-widget::after { content: ''; position: absolute; right: -20px; top: -20px; width: 100px; height: 100px; border-radius: 50%; background: rgba(255,255,255,.1); }
.stat-widget .sw-icon { font-size: 2.5rem; opacity: .8; position: relative; z-index: 1; }
.stat-widget .sw-num { font-size: 2rem; font-weight: 800; line-height: 1; position: relative; z-index: 1; }

/* Admin table */
.admin-table { font-size: .875rem; }
.admin-table th {
  background: var(--light-bg); font-weight: 600; color: var(--gray);
  font-size: .75rem; text-transform: uppercase; letter-spacing: .5px;
  white-space: nowrap; border-bottom: 2px solid var(--border) !important;
}
.admin-table td { vertical-align: middle; }
.table-responsive { border-radius: var(--radius); overflow: hidden; border: 1px solid var(--border); }

/* Admin question block */
.question-block { border-left: 4px solid var(--primary); transition: border-color .2s; }
.question-block:hover { border-color: var(--secondary); }
.question-block .card-header { background: #f8f9ff; }
.option-row:has(input[type=radio]:checked) .form-control { border-color: #16a34a; background: #f0fdf4; }
.option-row:has(input[type=radio]:checked) .option-letter { color: #16a34a !important; }

/* ── Badges ─────────────────────────────────────────── */
.badge-free { background: #dcfce7 !important; color: #166534 !important; }
.badge-paid { background: #fef3c7 !important; color: #92400e !important; }

/* ── Footer ─────────────────────────────────────────── */
.footer { background: var(--dark); color: rgba(255,255,255,.7); margin-top: auto; }
.footer h5, .footer h6 { color: white; }
.footer-links a { color: rgba(255,255,255,.6); font-size: .875rem; display: block; margin-bottom: 8px; transition: color .2s; }
.footer-links a:hover { color: white; padding-left: 4px; }

/* ── Utilities ──────────────────────────────────────── */
.text-primary { color: var(--primary) !important; }
.bg-primary   { background: var(--primary) !important; }
.fw-500       { font-weight: 500; }
.fw-600       { font-weight: 600; }
.text-gradient {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}

/* ── Responsive ─────────────────────────────────────── */
@media (max-width: 991px) {
  .admin-sidebar { transform: translateX(-100%); }
  .admin-sidebar.open { transform: translateX(0); }
  .admin-content { margin-left: 0; }
  .admin-topbar { padding: 10px 16px; }
  .admin-main { padding: 16px; }
}
@media (max-width: 768px) {
  .hero { padding: 50px 0; }
  .hero h1 { font-size: 2rem; }
  .auth-card { padding: 24px; margin: 16px; }
  .section-title { font-size: 1.4rem; }
}
@media (max-width: 480px) {
  .auth-card { padding: 20px 16px; }
}