/* ============================================
   ALL QUIZZES LANDING PAGE — Design System
   ============================================
   Following the frontend-design skill direction:
   - Display: JetBrains Mono (code-native, characterful)
   - Body: Inter (readable, neutral)
   - Accent signature: pastel rose (#f5ccc8) for active states
   - Pastel category colors (no purple, cyan, or lime)
   - Floating question-mark ambient background
   ============================================ */

/* ─── CSS Variables (scoped to quizzes page) ─── */
[data-page="quizzes"] {
  --qz-bg: #0a0a14;
  --qz-surface: #14141f;
  --qz-elevated: #1c1c2e;
  --qz-primary: #f5ccc8;
  --qz-primary-rgb: 245, 204, 200;
  --qz-accent: #d4b8b8;
  --qz-accent-rgb: 212, 184, 184;
  --qz-emerald: #7ec8a8;
  --qz-emerald-rgb: 126, 200, 168;
  --qz-text: #f1f5f9;
  --qz-text-muted: #64748b;
  --qz-border: rgba(148, 163, 184, 0.15);
  --qz-border-hover: rgba(148, 163, 184, 0.28);
  --qz-radius: 12px;
  --qz-radius-lg: 20px;
  --qz-pastel-blue: #c8d8e8;
  --qz-pastel-blue-rgb: 200, 216, 232;
  --qz-pastel-peach: #f5d8b8;
  --qz-pastel-peach-rgb: 245, 216, 184;
  --qz-pastel-tan: #e8d0c0;
  --qz-pastel-tan-rgb: 232, 208, 192;
  --qz-pastel-sage: #c8e0d0;
  --qz-pastel-sage-rgb: 200, 224, 208;
  --qz-pastel-ivory: #e8e0c8;
  --qz-pastel-ivory-rgb: 232, 224, 200;

  /* Difficulty colors */
  --qz-diff-easy: #7ec8a8;
  --qz-diff-easy-rgb: 126, 200, 168;
  --qz-diff-medium: #e8c888;
  --qz-diff-medium-rgb: 232, 200, 136;
  --qz-diff-hard: #e8a8a0;
  --qz-diff-hard-rgb: 232, 168, 160;
}

/* ─── Hero Section ─── */
[data-page="quizzes"] .qz-hero {
  position: relative;
  padding: 8rem 1.5rem 3rem;
  text-align: center;
  overflow: hidden;
  background: var(--qz-bg);
  min-height: 60vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.qz-hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
}

.qz-hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(245, 204, 200, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 204, 200, 0.025) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 60% 50% at 50% 40%, black 30%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse 60% 50% at 50% 40%, black 30%, transparent 70%);
}

/* ─── Full-page Question Marks Background ─── */
.qz-bg-questions {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
  opacity: 0.03;
  font-family: 'JetBrains Mono', monospace;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--qz-text);
}

.qz-bg-questions::before {
  content: "?";
  position: absolute;
  top: 8%;
  left: 5%;
  font-size: 6rem;
  opacity: 0.6;
  transform: rotate(-15deg);
}

.qz-bg-questions::after {
  content: "?";
  position: absolute;
  bottom: 12%;
  right: 4%;
  font-size: 8rem;
  opacity: 0.4;
  transform: rotate(20deg);
}

.qz-hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
  width: 100%;
}

.qz-hero-title {
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: 1rem;
  letter-spacing: -1px;
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: center;
  cursor: default;
  color: #ffffff;
}

.qz-title-letter {
  display: inline-block;
  opacity: 0;
  transform: translateY(8px);
  animation:
    qzLetterReveal 0.5s cubic-bezier(0.16, 1, 0.3, 1) forwards,
    qzLetterColorWave 6s linear infinite;
  animation-delay:
    calc(var(--i, 0) * 0.04s),
    calc(var(--i, 0) * 0.15s + 0.8s);
  will-change: transform, opacity, color;
  backface-visibility: hidden;
  user-select: none;
}

@keyframes qzLetterReveal {
  0% {
    opacity: 0;
    transform: translateY(10px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes qzLetterColorWave {
  0%   { color: #ffffff; }
  12%  { color: #f5ccc8; } /* rose */
  37%  { color: #f5d8b8; } /* peach */
  62%  { color: #c8e0d0; } /* sage */
  87%  { color: #c8d8e8; } /* blue */
  100% { color: #ffffff; }
}

.qz-title-space {
  display: inline-block;
  width: 0.3em;
}

.qz-hero-subtitle {
  font-family: 'Inter', sans-serif;
  font-size: 1.05rem;
  color: var(--qz-text-muted);
  line-height: 1.6;
  max-width: 540px;
  margin: 0 auto 2rem;
}

.qz-hero-subtitle strong {
  color: var(--qz-primary);
  font-weight: 700;
}

/* ─── Search ─── */
.qz-search-wrapper {
  max-width: 480px;
  margin: 0 auto 1.5rem;
}

.qz-search {
  position: relative;
  display: flex;
  align-items: center;
  background: var(--qz-surface);
  border: 1px solid var(--qz-border);
  border-radius: 100px;
  transition: all 0.25s ease;
  overflow: hidden;
}

.qz-search:focus-within {
  border-color: var(--qz-primary);
  box-shadow: 0 0 0 3px rgba(245, 204, 200, 0.15), 0 4px 20px rgba(245, 204, 200, 0.06);
  background: #181828;
}

.qz-search-icon {
  position: absolute;
  left: 16px;
  color: var(--qz-text-muted);
  font-size: 0.9rem;
  pointer-events: none;
  transition: color 0.25s ease;
}

.qz-search:focus-within .qz-search-icon {
  color: var(--qz-primary);
}

.qz-search-input {
  flex: 1;
  padding: 0.85rem 3rem 0.85rem 2.75rem;
  background: transparent;
  border: none;
  color: var(--qz-text);
  font-family: 'Inter', sans-serif;
  font-size: 0.95rem;
  outline: none;
}

.qz-search-input::placeholder {
  color: var(--qz-text-muted);
  opacity: 0.6;
}

.qz-clear-btn {
  position: absolute;
  right: 44px;
  background: none;
  border: none;
  color: var(--qz-text-muted);
  cursor: pointer;
  padding: 4px 6px;
  font-size: 0.85rem;
  border-radius: 50%;
  display: none;
  transition: all 0.2s ease;
}

.qz-clear-btn:hover {
  color: #ef4444;
  background: rgba(239, 68, 68, 0.1);
}

.qz-clear-btn.visible {
  display: flex;
}

.qz-search-hint {
  position: absolute;
  right: 14px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem;
  color: var(--qz-text-muted);
  opacity: 0.4;
  pointer-events: none;
  padding: 2px 6px;
  border: 1px solid var(--qz-border);
  border-radius: 4px;
}

/* ─── Filter Rows ─── */
.qz-filters {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.4rem;
  padding: 0 0.5rem;
}

.qz-filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  flex: 0 1 auto;
}

.qz-filter-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  padding: 0.3rem 0.5rem 0.3rem 0;
  border-right: 1px solid rgba(255,255,255,0.06);
  margin-right: 0.25rem;
  user-select: none;
}

#qzFilters .qz-filter-label {
  color: var(--qz-primary);
  opacity: 0.65;
}

#qzDifficultyFilters .qz-filter-label {
  color: var(--qz-pastel-sage);
  opacity: 0.8;
}

.qz-filter-chip {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  font-weight: 500;
  padding: 0.4rem 0.8rem;
  border-radius: 100px;
  background: transparent;
  border: 1px solid var(--qz-border);
  color: var(--qz-text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.qz-filter-chip:hover {
  border-color: var(--qz-pastel-blue);
  color: var(--qz-pastel-blue);
  background: rgba(var(--qz-pastel-blue-rgb), 0.08);
}

.qz-filter-chip.active {
  background: rgba(var(--qz-primary-rgb), 0.15);
  border-color: var(--qz-primary);
  color: var(--qz-primary);
  box-shadow: 0 0 12px rgba(245, 204, 200, 0.1);
}

.qz-result-count {
  font-family: 'Inter', sans-serif;
  font-size: 0.85rem;
  color: var(--qz-text-muted);
  margin-top: 0.5rem;
}

.qz-result-count span {
  color: var(--qz-emerald);
  font-weight: 600;
  font-family: 'JetBrains Mono', monospace;
}

/* ─── Difficulty Filter Chips ─── */
.qz-difficulty-chip {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  font-weight: 500;
  padding: 0.4rem 0.8rem;
  border-radius: 100px;
  background: transparent;
  border: 1px solid var(--qz-border);
  color: var(--qz-text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.qz-difficulty-chip[data-difficulty="easy"]:hover {
  border-color: var(--qz-diff-easy);
  color: var(--qz-diff-easy);
  background: rgba(var(--qz-diff-easy-rgb), 0.08);
}
.qz-difficulty-chip[data-difficulty="easy"].active {
  background: rgba(var(--qz-diff-easy-rgb), 0.15);
  border-color: var(--qz-diff-easy);
  color: var(--qz-diff-easy);
  box-shadow: 0 0 10px rgba(var(--qz-diff-easy-rgb), 0.1);
}

.qz-difficulty-chip[data-difficulty="medium"]:hover {
  border-color: var(--qz-diff-medium);
  color: var(--qz-diff-medium);
  background: rgba(var(--qz-diff-medium-rgb), 0.08);
}
.qz-difficulty-chip[data-difficulty="medium"].active {
  background: rgba(var(--qz-diff-medium-rgb), 0.15);
  border-color: var(--qz-diff-medium);
  color: var(--qz-diff-medium);
  box-shadow: 0 0 10px rgba(var(--qz-diff-medium-rgb), 0.1);
}

.qz-difficulty-chip[data-difficulty="hard"]:hover {
  border-color: var(--qz-diff-hard);
  color: var(--qz-diff-hard);
  background: rgba(var(--qz-diff-hard-rgb), 0.08);
}
.qz-difficulty-chip[data-difficulty="hard"].active {
  background: rgba(var(--qz-diff-hard-rgb), 0.15);
  border-color: var(--qz-diff-hard);
  color: var(--qz-diff-hard);
  box-shadow: 0 0 10px rgba(var(--qz-diff-hard-rgb), 0.1);
}

.qz-difficulty-chip[data-difficulty="all"]:hover {
  border-color: var(--qz-primary);
  color: var(--qz-primary);
  background: rgba(var(--qz-primary-rgb), 0.08);
}
.qz-difficulty-chip[data-difficulty="all"].active {
  background: rgba(var(--qz-primary-rgb), 0.15);
  border-color: var(--qz-primary);
  color: var(--qz-primary);
  box-shadow: 0 0 10px rgba(var(--qz-primary-rgb), 0.1);
}

/* ─── Section ─── */
.qz-section {
  padding: 2rem 1.5rem 5rem;
  background: var(--qz-bg);
}

.qz-container {
  max-width: 1200px;
  margin: 0 auto;
}

/* ─── Card Grid ─── */
.qz-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

@media (min-width: 1024px) {
  .qz-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .qz-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 480px) {
  .qz-grid {
    grid-template-columns: 1fr;
  }
}

/* ─── Card ─── */
.qz-card {
  position: relative;
  background: var(--qz-surface);
  border: 1px solid var(--qz-border);
  border-radius: var(--qz-radius);
  padding: 1.5rem;
  cursor: pointer;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.25s ease, box-shadow 0.25s ease;
  isolation: isolate;
  overflow: hidden;
}

.qz-card::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: var(--qz-radius);
  background: linear-gradient(135deg, rgba(var(--qz-primary-rgb), 0.06), transparent 60%);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: -1;
}

.qz-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 32px rgba(0, 0, 0, 0.35);
}

.qz-card:hover::before {
  opacity: 1;
}

.qz-card:focus-visible {
  outline: 2px solid var(--qz-primary);
  outline-offset: 2px;
}

.qz-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.15rem;
}

.qz-card-icon {
  font-size: 1.35rem;
  line-height: 1;
  color: inherit;
  flex-shrink: 0;
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.qz-card:hover .qz-card-icon {
  transform: translateY(-2px);
}

.qz-card-difficulty {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6rem;
  font-weight: 500;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  white-space: nowrap;
  flex-shrink: 0;
  text-transform: uppercase;
  letter-spacing: 0.3px;
}

.qz-card-difficulty.easy {
  color: var(--qz-diff-easy);
  background: rgba(var(--qz-diff-easy-rgb), 0.1);
  border: 1px solid rgba(var(--qz-diff-easy-rgb), 0.15);
}

.qz-card-difficulty.medium {
  color: var(--qz-diff-medium);
  background: rgba(var(--qz-diff-medium-rgb), 0.1);
  border: 1px solid rgba(var(--qz-diff-medium-rgb), 0.15);
}

.qz-card-difficulty.hard {
  color: var(--qz-diff-hard);
  background: rgba(var(--qz-diff-hard-rgb), 0.1);
  border: 1px solid rgba(var(--qz-diff-hard-rgb), 0.15);
}

.qz-card-title {
  font-family: 'Inter', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--qz-text);
  line-height: 1.3;
}

.qz-card-desc {
  font-family: 'Inter', sans-serif;
  font-size: 0.78rem;
  color: var(--qz-text-muted);
  line-height: 1.5;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.qz-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--qz-border);
}

.qz-card-category {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  max-width: 60%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.qz-card-question-count {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6rem;
  font-weight: 500;
  color: var(--qz-text-muted);
  display: flex;
  align-items: center;
  gap: 0.3rem;
  flex-shrink: 0;
}

.qz-card-question-count i {
  font-size: 0.55rem;
  opacity: 0.6;
}

.qz-card-arrow {
  color: var(--qz-text-muted);
  font-size: 0.75rem;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.qz-card:hover .qz-card-arrow {
  color: var(--qz-primary);
  transform: translateX(3px);
}

/* ─── Category-themed card hover: tinted background ─── */
.qz-card[data-category="data-structures"]:hover {
  border-color: rgba(200, 216, 232, 0.35);
}
.qz-card[data-category="data-structures"] .qz-card-category {
  color: var(--qz-pastel-blue);
  border-color: rgba(var(--qz-pastel-blue-rgb), 0.25);
  background: rgba(var(--qz-pastel-blue-rgb), 0.08);
}
.qz-card[data-category="data-structures"]:hover::before {
  background: linear-gradient(135deg, rgba(var(--qz-pastel-blue-rgb), 0.08), transparent 60%);
}

.qz-card[data-category="core-algorithms"]:hover {
  border-color: rgba(245, 216, 184, 0.35);
}
.qz-card[data-category="core-algorithms"] .qz-card-category {
  color: var(--qz-pastel-peach);
  border-color: rgba(var(--qz-pastel-peach-rgb), 0.25);
  background: rgba(var(--qz-pastel-peach-rgb), 0.08);
}
.qz-card[data-category="core-algorithms"]:hover::before {
  background: linear-gradient(135deg, rgba(var(--qz-pastel-peach-rgb), 0.08), transparent 60%);
}

.qz-card[data-category="advanced"]:hover {
  border-color: rgba(232, 208, 192, 0.35);
}
.qz-card[data-category="advanced"] .qz-card-category {
  color: var(--qz-pastel-tan);
  border-color: rgba(var(--qz-pastel-tan-rgb), 0.25);
  background: rgba(var(--qz-pastel-tan-rgb), 0.08);
}
.qz-card[data-category="advanced"]:hover::before {
  background: linear-gradient(135deg, rgba(var(--qz-pastel-tan-rgb), 0.08), transparent 60%);
}

.qz-card[data-category="special"]:hover {
  border-color: rgba(200, 224, 208, 0.35);
}
.qz-card[data-category="special"] .qz-card-category {
  color: var(--qz-pastel-sage);
  border-color: rgba(var(--qz-pastel-sage-rgb), 0.25);
  background: rgba(var(--qz-pastel-sage-rgb), 0.08);
}
.qz-card[data-category="special"]:hover::before {
  background: linear-gradient(135deg, rgba(var(--qz-pastel-sage-rgb), 0.08), transparent 60%);
}

/* ─── Empty State ─── */
.qz-empty {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--qz-text-muted);
}

.qz-empty i {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  opacity: 0.4;
}

.qz-empty h3 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.2rem;
  color: var(--qz-text);
  margin-bottom: 0.5rem;
}

.qz-empty p {
  font-family: 'Inter', sans-serif;
  font-size: 0.9rem;
}

/* ─── Card Animation ─── */
[data-page="quizzes"] .qz-card {
  animation: qzCardFadeIn 0.35s ease both;
}

@keyframes qzCardFadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ─── Responsive ─── */
@media (max-width: 768px) {
  [data-page="quizzes"] .qz-hero {
    padding: 6rem 1rem 2.5rem;
    min-height: auto;
  }

  .qz-hero-title {
    font-size: 2rem;
  }

  .qz-hero-subtitle {
    font-size: 0.9rem;
  }

  .qz-search-input {
    font-size: 0.9rem;
    padding: 0.75rem 2.5rem 0.75rem 2.5rem;
  }

  .qz-filters {
    gap: 0.35rem;
  }

  .qz-filter-chips {
    gap: 0.35rem;
  }

  .qz-filter-chip {
    font-size: 0.7rem;
    padding: 0.35rem 0.75rem;
  }

  .qz-grid {
    gap: 0.75rem;
  }

  .qz-search-hint {
    display: none;
  }
}

/* ─── Back Button ─── */
.qz-back-btn {
  position: absolute;
  top: 2rem;
  left: 1.5rem;
  z-index: 10;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 1rem 0.55rem 0.85rem;
  background: var(--qz-surface);
  border: 1px solid var(--qz-border);
  border-radius: 100px;
  color: var(--qz-text-muted);
  font-family: 'Inter', sans-serif;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.2s ease;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.qz-back-btn i {
  font-size: 0.85rem;
  transition: transform 0.2s ease;
}

.qz-back-btn span {
  font-weight: 500;
}

.qz-back-btn:hover {
  border-color: var(--qz-primary);
  color: var(--qz-primary);
  background: rgba(var(--qz-primary-rgb), 0.08);
}

.qz-back-btn:hover i {
  transform: translateX(-3px);
}

.qz-back-btn:focus-visible {
  outline: 2px solid var(--qz-primary);
  outline-offset: 2px;
}

@media (max-width: 768px) {
  .qz-back-btn {
    top: 1rem;
    left: 0.75rem;
    padding: 0.45rem 0.75rem 0.45rem 0.65rem;
    font-size: 0.8rem;
  }
  .qz-back-btn span {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .qz-back-btn {
    transition: none;
  }
  .qz-back-btn i {
    transition: none;
  }
  .qz-back-btn:hover i {
    transform: none;
  }

  .qz-bg-questions {
    display: none;
  }

  .qz-title-letter {
    opacity: 1;
    transform: none;
    animation: none;
    color: inherit;
  }

  .qz-card {
    animation: none;
  }

  .qz-card:hover {
    transform: none;
  }

  .qz-card:hover .qz-card-icon {
    transform: none;
  }

  .qz-card:hover .qz-card-arrow {
    transform: none;
  }

  .qz-search {
    transition: none;
  }

  .qz-filter-chip {
    transition: none;
  }
}