@layer components {
  /* ============================================================
     GLOSSARY / COMPENDIUM — Layout & Components
     ============================================================ */

  /* Layout — constrained to max-width like header/footer */
  .glossary-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 0;
    min-height: calc(100vh - var(--header-height));
    max-width: var(--max-width);
    margin: 0 auto;
    padding-left: var(--space-4);
    padding-right: var(--space-4);
  }

  @media (max-width: 1023px) {
    .glossary-layout {
      grid-template-columns: 1fr;
      max-width: 100%;
    }
  }

  /* Sidebar */
  .glossary-sidebar {
    position: sticky;
    top: var(--header-height);
    height: calc(100vh - var(--header-height));
    overflow-y: auto;
    padding: var(--space-6);
    background: var(--bg-surface);
    border-right: 1px solid var(--border-color);
    z-index: 10;
  }

  @media (max-width: 1023px) {
    .glossary-sidebar {
      position: relative;
      top: 0;
      height: auto;
      border-right: none;
      border-bottom: 1px solid var(--border-color);
    }
  }

  .glossary-sidebar__header {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--border-color);
  }

  .glossary-sidebar__header i {
    font-size: var(--text-2xl);
    color: var(--challenge-primary);
  }

  .glossary-sidebar__header h2 {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--text-primary);
  }

  /* Search */
  .glossary-search {
    position: relative;
    margin-bottom: var(--space-4);
  }

  .glossary-search i {
    position: absolute;
    left: var(--space-3);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: var(--text-lg);
  }

  .glossary-search input {
    width: 100%;
    padding: var(--space-2) var(--space-3) var(--space-2) var(--space-10);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-body);
    color: var(--text-primary);
    font-size: var(--text-sm);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  }

  .glossary-search input:focus {
    outline: none;
    border-color: var(--challenge-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
  }

  .glossary-search input::placeholder {
    color: var(--text-muted);
  }

  /* Progress */
  .glossary-progress {
    margin-bottom: var(--space-6);
  }

  .glossary-progress__bar {
    width: 100%;
    height: 6px;
    background: var(--bg-code);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-bottom: var(--space-2);
  }

  .glossary-progress__fill {
    height: 100%;
    background: linear-gradient(90deg, var(--challenge-primary), var(--challenge-accent));
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
  }

  .glossary-progress__text {
    font-size: var(--text-xs);
    color: var(--text-muted);
    font-weight: 500;
  }

  /* Sidebar Nav */
  .glossary-nav {
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
  }

  .glossary-nav__item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast), background var(--transition-fast);
  }

  .glossary-nav__item:hover,
  .glossary-nav__item:focus {
    color: var(--text-primary);
    background: var(--bg-code);
  }

  .glossary-nav__item.is-active {
    color: var(--challenge-primary);
    background: rgba(79, 70, 229, 0.08);
  }

  .glossary-nav__item i {
    font-size: var(--text-lg);
  }

  /* Content Area */
  .glossary-content {
    padding: var(--space-8) var(--space-6);
    max-width: 900px;
    margin: 0 auto;
  }

  @media (min-width: 1024px) {
    .glossary-content {
      padding: var(--space-10) var(--space-12);
    }
  }

  .glossary-content__hero {
    margin-bottom: var(--space-10);
    padding-bottom: var(--space-8);
    border-bottom: 1px solid var(--border-color);
  }

  .glossary-content__title {
    font-size: var(--text-4xl);
    font-weight: 800;
    margin-bottom: var(--space-3);
    background: linear-gradient(135deg, var(--challenge-primary), var(--challenge-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
  }

  .glossary-content__subtitle {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    max-width: 600px;
  }

  /* Section */
  .glossary-section {
    margin-bottom: var(--space-12);
  }

  .glossary-section__title {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-size: var(--text-2xl);
    font-weight: 700;
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-4);
    border-bottom: 2px solid var(--border-color);
    color: var(--text-primary);
  }

  .glossary-section__title i {
    font-size: var(--text-xl);
    color: var(--challenge-primary);
  }

  /* Card */
  .glossary-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    margin-bottom: var(--space-6);
    transition: box-shadow var(--transition-base);
  }

  .glossary-card:hover {
    box-shadow: var(--shadow-md);
  }

  .glossary-card__title {
    font-size: var(--text-xl);
    font-weight: 700;
    margin-bottom: var(--space-3);
    color: var(--text-primary);
  }

  .glossary-card__tags {
    display: flex;
    gap: var(--space-2);
    margin-bottom: var(--space-4);
  }

  .glossary-card__tag {
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: rgba(79, 70, 229, 0.1);
    color: var(--challenge-primary);
  }

  .glossary-card__content {
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
  }

  .glossary-card__content h4 {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-top: var(--space-5);
    margin-bottom: var(--space-2);
    color: var(--text-primary);
  }

  .glossary-card__content p {
    margin-bottom: var(--space-3);
  }

  .glossary-card__content ol,
  .glossary-card__content ul {
    margin-left: var(--space-5);
    margin-bottom: var(--space-4);
  }

  .glossary-card__content li {
    margin-bottom: var(--space-2);
  }

  .glossary-card__content a {
    color: var(--challenge-primary);
    text-decoration: underline;
    text-underline-offset: 2px;
  }

  .glossary-card__content kbd {
    display: inline-block;
    padding: 2px 6px;
    background: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.85em;
    box-shadow: 0 2px 0 var(--border-color);
  }

  /* Tip Box */
  .glossary-card__tip {
    display: flex;
    gap: var(--space-3);
    padding: var(--space-4);
    margin-top: var(--space-5);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.05), rgba(6, 182, 212, 0.05));
    border-left: 3px solid var(--challenge-primary);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
  }

  .glossary-card__tip i {
    font-size: var(--text-xl);
    color: var(--challenge-primary);
    flex-shrink: 0;
  }

  /* Code Block — Premium syntax highlighting container */
  .code-block {
    position: relative;
    margin: var(--space-4) 0;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    border: 1px solid rgba(148, 163, 184, 0.15);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: inset 0 1px 0 rgba(255,255,255,0.03), 0 4px 12px rgba(0,0,0,0.15);
  }

  /* Code block header bar */
  .code-block::before {
    content: '';
    display: block;
    height: 36px;
    background: linear-gradient(180deg, rgba(30, 41, 59, 0.8), rgba(15, 23, 42, 0.6));
    border-bottom: 1px solid rgba(148, 163, 184, 0.1);
  }

  /* Window dots */
  .code-block::after {
    content: '';
    position: absolute;
    top: 14px;
    left: var(--space-4);
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #ef4444;
    box-shadow: 16px 0 0 #f59e0b, 32px 0 0 #10b981;
  }

  .code-block__copy {
    position: absolute;
    top: 6px;
    right: var(--space-3);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: var(--radius-md);
    background: rgba(255, 255, 255, 0.06);
    color: var(--challenge-gray-400);
    transition: background var(--transition-fast), color var(--transition-fast);
    z-index: 1;
  }

  .code-block__copy:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #e2e8f0;
  }

  .code-block pre {
    margin: 0;
    padding: var(--space-4) var(--space-5);
    overflow-x: auto;
    background: none;
  }

  .code-block code {
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    line-height: 1.7;
    color: #e2e8f0;
    background: none;
    padding: 0;
  }

  /* Table */
  .glossary-table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-4) 0;
    font-size: var(--text-sm);
  }

  .glossary-table th,
  .glossary-table td {
    padding: var(--space-3) var(--space-4);
    text-align: left;
    border-bottom: 1px solid var(--border-color);
  }

  .glossary-table th {
    font-weight: 600;
    color: var(--text-primary);
    background: var(--bg-code);
  }

  .glossary-table td {
    color: var(--text-secondary);
  }

  .glossary-table code {
    font-size: 0.9em;
  }

  /* ITCSS Triangle */
  .glossary-triangle {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-2);
    margin: var(--space-6) 0;
    padding: var(--space-6);
    background: var(--bg-code);
    border-radius: var(--radius-lg);
  }

  .glossary-triangle__layer {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    text-align: center;
    font-size: var(--text-sm);
    color: white;
    transition: transform var(--transition-fast);
  }

  .glossary-triangle__layer:hover {
    transform: scale(1.02);
  }

  .glossary-triangle__layer strong {
    display: block;
    font-size: var(--text-base);
    margin-bottom: 2px;
  }

  .glossary-triangle__layer--1 {
    width: 40%;
    background: linear-gradient(135deg, #64748b, #94a3b8);
  }

  .glossary-triangle__layer--2 {
    width: 50%;
    background: linear-gradient(135deg, #475569, #64748b);
  }

  .glossary-triangle__layer--3 {
    width: 60%;
    background: linear-gradient(135deg, #334155, #475569);
  }

  .glossary-triangle__layer--4 {
    width: 70%;
    background: linear-gradient(135deg, #1e293b, #334155);
  }

  .glossary-triangle__layer--5 {
    width: 80%;
    background: linear-gradient(135deg, #3730a3, #4f46e5);
  }

  .glossary-triangle__layer--6 {
    width: 90%;
    background: linear-gradient(135deg, #4f46e5, #6366f1);
  }

  .glossary-triangle__layer--7 {
    width: 100%;
    background: linear-gradient(135deg, #0891b2, #06b6d4);
  }

  /* BEM Diagram */
  .glossary-bem {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-4);
    margin: var(--space-6) 0;
  }

  .glossary-bem__block,
  .glossary-bem__element,
  .glossary-bem__modifier {
    padding: var(--space-5);
    border-radius: var(--radius-lg);
    text-align: center;
  }

  .glossary-bem__block {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.1), rgba(79, 70, 229, 0.05));
    border: 2px solid var(--challenge-primary);
  }

  .glossary-bem__element {
    background: linear-gradient(135deg, rgba(6, 182, 212, 0.1), rgba(6, 182, 212, 0.05));
    border: 2px solid var(--challenge-accent);
  }

  .glossary-bem__modifier {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(16, 185, 129, 0.05));
    border: 2px solid var(--challenge-success);
  }

  .glossary-bem__label {
    font-size: var(--text-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-2);
    color: var(--text-muted);
  }

  .glossary-bem code {
    display: block;
    font-size: var(--text-base);
    font-weight: 600;
    margin-bottom: var(--space-2);
    background: none;
    padding: 0;
  }

  .glossary-bem span {
    font-size: var(--text-sm);
    color: var(--text-secondary);
  }

  /* Quiz */
  .glossary-quiz {
    margin-top: var(--space-6);
    padding-top: var(--space-6);
    border-top: 1px solid var(--border-color);
  }

  .glossary-quiz__title {
    font-size: var(--text-base);
    font-weight: 600;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
  }

  .glossary-quiz__question p {
    font-size: var(--text-base);
    color: var(--text-secondary);
    margin-bottom: var(--space-4);
  }

  .glossary-quiz__options {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
  }

  .glossary-quiz__option {
    padding: var(--space-3) var(--space-4);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-body);
    color: var(--text-secondary);
    font-size: var(--text-sm);
    text-align: left;
    transition: border-color var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
  }

  .glossary-quiz__option:hover {
    border-color: var(--challenge-primary);
    color: var(--text-primary);
  }

  .glossary-quiz__option.is-correct {
    border-color: var(--challenge-success);
    background: rgba(16, 185, 129, 0.1);
    color: var(--challenge-success);
  }

  .glossary-quiz__option.is-wrong {
    border-color: var(--challenge-error);
    background: rgba(239, 68, 68, 0.1);
    color: var(--challenge-error);
  }

  .glossary-quiz__option.is-disabled {
    pointer-events: none;
    opacity: 0.7;
  }

  .glossary-quiz__feedback {
    margin-top: var(--space-3);
    font-size: var(--text-sm);
    font-weight: 500;
    min-height: 1.5em;
  }

  .glossary-quiz__feedback.is-correct {
    color: var(--challenge-success);
  }

  .glossary-quiz__feedback.is-wrong {
    color: var(--challenge-error);
  }

  /* ── Dark Mode Overrides ── */
  html.dark-mode .glossary-sidebar {
    background: linear-gradient(180deg, rgba(30, 41, 59, 0.9), rgba(15, 23, 42, 0.95));
    border-color: rgba(255, 255, 255, 0.06);
  }

  html.dark-mode .glossary-content {
    background: transparent;
  }

  html.dark-mode .glossary-card {
    background: linear-gradient(135deg, rgba(30, 41, 59, 0.8), rgba(15, 23, 42, 0.9));
    border-color: rgba(255, 255, 255, 0.06);
    box-shadow: 0 4px 20px -4px rgba(0, 0, 0, 0.3);
  }

  html.dark-mode .glossary-card:hover {
    box-shadow: 0 8px 30px -4px rgba(0, 0, 0, 0.4), 0 0 0 1px rgba(79, 70, 229, 0.15);
    border-color: rgba(129, 140, 248, 0.15);
  }

  html.dark-mode .glossary-card__tag {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.15), rgba(6, 182, 212, 0.1));
    color: var(--challenge-primary-light);
  }

  html.dark-mode .glossary-card__tip {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.08), rgba(6, 182, 212, 0.08));
    border-left-color: var(--challenge-primary-light);
  }

  html.dark-mode .glossary-nav__item:hover,
  html.dark-mode .glossary-nav__item:focus {
    background: rgba(79, 70, 229, 0.08);
    color: var(--text-primary);
  }

  html.dark-mode .glossary-nav__item.is-active {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.15), rgba(6, 182, 212, 0.1));
    color: var(--challenge-primary-light);
  }

  html.dark-mode .glossary-search input {
    background: rgba(15, 23, 42, 0.6);
    border-color: rgba(255, 255, 255, 0.08);
  }

  html.dark-mode .glossary-search input:focus {
    border-color: var(--challenge-primary-light);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
  }

  html.dark-mode .glossary-content__title {
    filter: brightness(1.2);
  }

  html.dark-mode .glossary-quiz__option {
    background: rgba(30, 41, 59, 0.6);
    border-color: rgba(255, 255, 255, 0.06);
  }

  html.dark-mode .glossary-quiz__option:hover {
    border-color: var(--challenge-primary-light);
    background: rgba(79, 70, 229, 0.08);
  }

  html.dark-mode .glossary-table th {
    background: rgba(30, 41, 59, 0.8);
  }

  /* Search Highlight */
  .glossary-card.is-hidden {
    display: none;
  }

  .glossary-card.is-highlighted {
    box-shadow: 0 0 0 2px var(--challenge-primary), var(--shadow-lg);
  }

  /* Active Nav Item in main nav */
  .main-nav .nav-link.is-active {
    color: var(--challenge-primary);
    background: rgba(79, 70, 229, 0.08);
  }
}