/* ============================================================
   BLD.CSS — Premium Styles for BLD Practice Portals
   ============================================================
   Used by BLD-QP.html (full practice with answers) and
   BLD-PP.html (exam mode, no answers).
   ============================================================ */

/* ============================================================
   1. ROOT VARIABLES (matches main site)
   ============================================================ */
:root {
  --color-bg: #f1f5f9;
  --color-bg-surface: #ffffff;
  --color-bg-glass: rgba(255, 255, 255, 0.60);
  --color-bg-glass-light: rgba(255, 255, 255, 0.30);
  --color-text-primary: #0b0f1a;
  --color-text-secondary: #2a3346;
  --color-text-muted: #6b7a93;
  --color-border: #e8edf4;
  --color-glass-border: rgba(255, 255, 255, 0.40);
  --color-glass-border-hover: rgba(255, 255, 255, 0.70);
  --color-accent: #2563eb;
  --color-accent-light: #dbeafe;
  --color-accent-gradient: linear-gradient(135deg, #2563eb, #7c3aed);
  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-shadow: 0 8px 32px rgba(0, 0, 0, 0.04);
  --color-shadow-hover: 0 16px 48px rgba(0, 0, 0, 0.10);
  --color-glow: rgba(37, 99, 235, 0.15);
  --radius-card: 18px;
  --radius-button: 10px;
  --radius-badge: 100px;
  --font-family: 'Inter', system-ui, -apple-system, sans-serif;
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-bounce: 0.6s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  --transition-magnetic: 0.4s cubic-bezier(0.25, 1.25, 0.5, 1);
}

.dark {
  --color-bg: #070b12;
  --color-bg-surface: #151e2d;
  --color-bg-glass: rgba(21, 30, 45, 0.70);
  --color-bg-glass-light: rgba(21, 30, 45, 0.35);
  --color-text-primary: #f0f4ff;
  --color-text-secondary: #bcc8e0;
  --color-text-muted: #7a8aa8;
  --color-border: #26324a;
  --color-glass-border: rgba(255, 255, 255, 0.08);
  --color-glass-border-hover: rgba(255, 255, 255, 0.16);
  --color-accent: #3b82f6;
  --color-accent-light: #1e3a5f;
  --color-shadow: 0 8px 32px rgba(0, 0, 0, 0.50);
  --color-shadow-hover: 0 16px 48px rgba(0, 0, 0, 0.60);
  --color-glow: rgba(59, 130, 246, 0.20);
}

/* ============================================================
   2. BASE & RESET
   ============================================================ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text-primary);
  min-height: 100vh;
  transition: background var(--transition-smooth), color var(--transition-smooth);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================================
   3. SCROLLBAR
   ============================================================ */
::-webkit-scrollbar {
  width: 5px;
  height: 5px;
}
::-webkit-scrollbar-track {
  background: var(--color-border);
  border-radius: 20px;
}
::-webkit-scrollbar-thumb {
  background: var(--color-text-muted);
  border-radius: 20px;
  transition: background var(--transition-smooth);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-accent);
}

/* ============================================================
   4. GLASS CARD
   ============================================================ */
.card-glass {
  background: var(--color-bg-glass);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border: 1px solid var(--color-glass-border);
  border-radius: var(--radius-card);
  box-shadow: var(--color-shadow);
  transition: all var(--transition-smooth);
}
.card-glass:hover {
  border-color: var(--color-glass-border-hover);
  box-shadow: var(--color-shadow-hover);
}

/* ============================================================
   5. STICKY NAV
   ============================================================ */
.sticky-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: var(--color-bg-glass);
  border-bottom: 1px solid var(--color-glass-border);
}

/* ============================================================
   6. DAY ACCORDION HEADER
   ============================================================ */
.day-header {
  cursor: pointer;
  user-select: none;
  transition: background var(--transition-smooth);
  border-radius: 16px;
}
.day-header:hover {
  background: var(--color-accent-light);
}
.day-header .chevron {
  transition: transform var(--transition-spring);
}
.day-header.open .chevron {
  transform: rotate(180deg);
}

/* ============================================================
   7. QUESTION TOGGLE
   ============================================================ */
.q-toggle {
  cursor: pointer;
  user-select: none;
  transition: background var(--transition-smooth);
  border-radius: 12px;
}
.q-toggle:hover {
  background: var(--color-bg-glass-light);
}
.q-toggle .q-chevron {
  transition: transform var(--transition-spring);
}
.q-toggle.open .q-chevron {
  transform: rotate(180deg);
}

/* ============================================================
   8. OPTION ITEMS (MCQ)
   ============================================================ */
.option-item {
  cursor: pointer;
  border: 1.5px solid var(--color-border);
  border-radius: 12px;
  padding: 12px 16px;
  transition: all var(--transition-smooth);
  background: var(--color-bg-glass-light);
  display: flex;
  align-items: flex-start;
  gap: 12px;
}
.option-item:hover {
  border-color: var(--color-text-muted);
  background: var(--color-accent-light);
  transform: translateY(-1px);
}
.option-item.selected {
  border-color: var(--color-accent);
  background: var(--color-accent-light);
  box-shadow: 0 0 0 1px var(--color-accent);
}
.option-item.selected .option-marker {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}
.option-item.correct-reveal {
  border-color: var(--color-success);
  background: #f0fdf4;
}
.option-item.correct-reveal .option-marker {
  background: var(--color-success);
  color: #fff;
  border-color: var(--color-success);
}
.option-item.wrong-reveal {
  border-color: var(--color-danger);
  background: #fef2f2;
}
.option-item.wrong-reveal .option-marker {
  background: var(--color-danger);
  color: #fff;
  border-color: var(--color-danger);
}
.option-item.disabled {
  cursor: default;
  opacity: 0.7;
}
.option-item.disabled:hover {
  transform: none;
  background: var(--color-bg-glass-light);
}
.option-marker {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 1.5px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--color-text-muted);
  transition: all var(--transition-smooth);
  background: var(--color-bg-surface);
}
.option-text {
  flex: 1;
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--color-text-primary);
  padding-top: 2px;
}

/* ============================================================
   9. ANSWER SLIDE (Explanation / Model Answer)
   ============================================================ */
.answer-slide {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.45s cubic-bezier(0.4, 0, 0.2, 1),
              opacity 0.35s ease,
              padding 0.3s ease;
  padding: 0 0 0 0;
}
.answer-slide.open {
  max-height: 2400px;
  opacity: 1;
  padding: 16px 0 4px 0;
}

/* ============================================================
   10. ILAC GRID
   ============================================================ */
.ilac-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
@media (max-width: 640px) {
  .ilac-grid {
    grid-template-columns: 1fr;
  }
}
.ilac-item {
  background: var(--color-bg-glass-light);
  border-radius: 12px;
  padding: 14px 16px;
  border-left: 4px solid var(--color-accent);
}
.ilac-item .ilac-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 4px;
}
.ilac-item .ilac-text {
  font-size: 0.92rem;
  line-height: 1.6;
  color: var(--color-text-primary);
}

/* ============================================================
   11. BADGES
   ============================================================ */
.badge-day {
  background: var(--color-accent-light);
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.7rem;
  padding: 2px 10px;
  border-radius: var(--radius-badge);
  letter-spacing: 0.02em;
}
.badge-complete {
  background: #dcfce7;
  color: #15803d;
  font-weight: 600;
  font-size: 0.7rem;
  padding: 2px 10px;
  border-radius: var(--radius-badge);
  letter-spacing: 0.02em;
}
.badge-progress {
  background: #fef9c3;
  color: #854d0e;
  font-weight: 600;
  font-size: 0.7rem;
  padding: 2px 10px;
  border-radius: var(--radius-badge);
  letter-spacing: 0.02em;
}
.dark .badge-complete {
  background: #064e3b;
  color: #34d399;
}
.dark .badge-progress {
  background: #713f12;
  color: #fbbf24;
}

/* ============================================================
   12. BUTTONS
   ============================================================ */
.btn-primary {
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.85rem;
  padding: 10px 24px;
  border-radius: var(--radius-badge);
  border: none;
  transition: all var(--transition-smooth);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.btn-primary:hover {
  background: #1e3a8a;
  transform: translateY(-1px);
  box-shadow: 0 8px 20px -8px rgba(30, 64, 175, 0.3);
}
.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}
.btn-secondary {
  background: var(--color-border);
  color: var(--color-text-secondary);
  font-weight: 500;
  font-size: 0.85rem;
  padding: 10px 24px;
  border-radius: var(--radius-badge);
  border: none;
  transition: all var(--transition-smooth);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.btn-secondary:hover {
  background: var(--color-text-muted);
  color: var(--color-bg-surface);
  transform: translateY(-1px);
}
.dark .btn-secondary {
  background: #1e293b;
  color: #94a3b8;
}
.dark .btn-secondary:hover {
  background: #334155;
  color: #e2e8f0;
}

/* ============================================================
   13. RESPONSIVE
   ============================================================ */
@media (max-width: 480px) {
  .option-item {
    padding: 10px 12px;
  }
  .option-text {
    font-size: 0.88rem;
  }
  .btn-primary,
  .btn-secondary {
    padding: 8px 16px;
    font-size: 0.8rem;
  }
}

/* ============================================================
   14. REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}