/* =========================================================
   components.css — premium UI components v2
   ========================================================= */

/* ----------- Buttons ----------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  white-space: nowrap;
  position: relative;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn--primary {
  background: var(--color-primary);
  color: white;
  box-shadow: 0 1px 2px rgba(109, 40, 217, 0.3), 0 4px 12px -2px rgba(109, 40, 217, 0.25);
}
.btn--primary:hover { background: var(--color-primary-dark); color: white; box-shadow: 0 4px 14px rgba(109, 40, 217, 0.4); }

.btn--gradient {
  background: var(--gradient-hero);
  color: #ffffff !important;
  box-shadow: 0 4px 14px rgba(167, 139, 250, 0.4);
  background-size: 200% 200%;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.45);
  font-weight: 800;
  -webkit-text-fill-color: #ffffff;   /* prevents iOS / Chrome gradient text bleed */
  -webkit-background-clip: border-box;
  background-clip: border-box;
}
.btn--gradient:hover {
  color: #ffffff !important;
  -webkit-text-fill-color: #ffffff;
  box-shadow: 0 8px 24px rgba(167, 139, 250, 0.5);
  background-position: right center;
}
.btn--gradient:visited, .btn--gradient:active, .btn--gradient:focus,
.btn--gradient:visited * { color: #ffffff !important; -webkit-text-fill-color: #ffffff; }
[data-theme="dark"] .btn--gradient { color: #ffffff !important; -webkit-text-fill-color: #ffffff; text-shadow: 0 1px 3px rgba(0,0,0,0.55); }

.btn--secondary {
  background: var(--color-surface);
  color: var(--color-text) !important;
  -webkit-text-fill-color: var(--color-text);
  border-color: var(--color-border-strong);
}
.btn--secondary:hover { background: var(--color-surface-2); color: var(--color-text); border-color: var(--color-primary-light); }
[data-theme="dark"] .btn--secondary {
  background: #18181B;
  color: #FAFAFA !important;
  -webkit-text-fill-color: #FAFAFA;
  border-color: rgba(255, 255, 255, 0.18);
}
[data-theme="dark"] .btn--secondary:hover { background: #27272A; color: #FFFFFF !important; -webkit-text-fill-color: #FFFFFF; }

.btn--ghost { background: transparent; color: var(--color-primary); }
.btn--ghost:hover { background: var(--color-primary-soft); color: var(--color-primary-dark); }

.btn--lg { padding: var(--space-4) var(--space-8); font-size: 1.05rem; }
.btn--sm { padding: var(--space-2) var(--space-3); font-size: 0.85rem; }

/* ----------- Badges ----------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 0.25rem 0.625rem;
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  background: var(--color-primary-soft);
  color: var(--color-primary-dark);
}
.badge--accent { background: #FEF3C7; color: var(--color-warning); }
.badge--success { background: #D1FAE5; color: var(--color-success); }
.badge--info { background: #CFFAFE; color: var(--color-accent-dark); }
.badge--danger { background: #FEE2E2; color: var(--color-danger); }
.badge--neutral { background: var(--color-surface-2); color: var(--color-text-muted); }

[data-theme="dark"] .badge { background: rgba(167, 139, 250, 0.15); color: #DDD6FE; }
[data-theme="dark"] .badge--accent { background: rgba(245, 158, 11, 0.15); color: #FCD34D; }
[data-theme="dark"] .badge--success { background: rgba(16, 185, 129, 0.15); color: #6EE7B7; }
[data-theme="dark"] .badge--info { background: rgba(6, 182, 212, 0.15); color: #67E8F9; }
[data-theme="dark"] .badge--danger { background: rgba(239, 68, 68, 0.15); color: #FCA5A5; }
[data-theme="dark"] .badge--neutral { background: var(--color-surface-2); color: var(--color-text-muted); }

/* ----------- Cards ----------- */
.card {
  background: var(--gradient-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: all var(--transition-base);
  box-shadow: var(--shadow-card);
}
.card:hover { border-color: var(--color-border-strong); box-shadow: var(--shadow-md); }

.card--interactive {
  cursor: pointer;
  display: block;
  text-decoration: none;
  color: inherit;
}
.card--interactive:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary-light);
  text-decoration: none;
  color: inherit;
}

.concept-card {
  position: relative;
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
}
.concept-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--gradient-hero);
  opacity: 0;
  transition: opacity var(--transition-base);
}
.card--interactive.concept-card:hover::before { opacity: 1; }
.concept-card__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px; height: 52px;
  border-radius: var(--radius-md);
  background: var(--gradient-soft);
  margin-bottom: var(--space-4);
  font-size: 1.6rem;
  border: 1px solid var(--color-border);
}
.concept-card__title { font-size: 1.25rem; margin: 0 0 var(--space-2); }
.concept-card__desc {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  flex: 1;
  margin-bottom: var(--space-4);
}
.concept-card__meta {
  display: flex;
  gap: var(--space-3);
  font-size: 0.8rem;
  color: var(--color-text-soft);
  align-items: center;
}
.concept-card__meta .badge { font-size: 0.7rem; padding: 2px 8px; }

/* ----------- Grid ----------- */
.grid { display: grid; gap: var(--space-6); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--auto-fit { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

@media (max-width: 900px) {
  .grid--3, .grid--4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
}

/* ----------- Hero ----------- */
.hero {
  position: relative;
  padding: var(--space-24) 0 var(--space-20);
  overflow: hidden;
  background: var(--color-bg);
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--gradient-mesh);
  opacity: 0.55;
  z-index: 0;
  pointer-events: none;
}
[data-theme="dark"] .hero::before { opacity: 0.30; }
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 80%, transparent 0, var(--color-bg) 70%);
  z-index: 0;
}
[data-theme="dark"] .hero::after {
  background: radial-gradient(circle at 20% 80%, transparent 0, var(--color-bg) 70%);
}
.hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: var(--space-12);
  align-items: center;
  position: relative;
  z-index: 1;
}
.hero__inner > * { min-width: 0; max-width: 100%; }
.hero__inner > div:first-child { overflow-wrap: anywhere; }
.hero h1 { overflow-wrap: break-word; word-break: keep-all; }
.hero__lead { overflow-wrap: anywhere; word-wrap: break-word; }
.hero__actions { flex-wrap: wrap; }
.hero__actions .btn { max-width: 100%; box-sizing: border-box; white-space: normal; }
@media (max-width: 900px) {
  .hero__inner { grid-template-columns: 1fr; gap: var(--space-8); }
}
.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  font-size: 0.875rem;
  font-weight: 600;
  color: #1C1917;
  margin-bottom: var(--space-5);
  backdrop-filter: blur(8px);
  box-shadow: var(--shadow-sm);
}
[data-theme="dark"] .hero__eyebrow {
  background: rgba(255, 255, 255, 0.10);
  color: #FFFFFF !important;
  border: 1px solid rgba(255, 255, 255, 0.22);
  box-shadow: 0 0 0 1px rgba(167, 139, 250, 0.18) inset, 0 4px 16px rgba(0, 0, 0, 0.4);
}
.hero h1 { margin-bottom: var(--space-5); }
.hero h1 .grad {
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  background-size: 200% 200%;
  animation: shimmer 6s ease infinite;
}
.hero__lead {
  font-size: 1.25rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  max-width: 560px;
  line-height: 1.6;
}
.hero__actions { display: flex; gap: var(--space-3); flex-wrap: wrap; }
.hero__stats {
  margin-top: var(--space-10);
  display: flex;
  gap: var(--space-8);
  flex-wrap: wrap;
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
}
.hero__stat strong {
  display: block;
  font-family: var(--font-display);
  font-size: 1.75rem;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 800;
}
.hero__stat span { font-size: 0.85rem; color: var(--color-text-muted); }

.hero__visual { position: relative; }
.hero__visual::before {
  content: "";
  position: absolute;
  inset: -20px;
  background: var(--gradient-hero);
  border-radius: var(--radius-xl);
  opacity: 0.15;
  filter: blur(40px);
  z-index: -1;
}
.code-card {
  background: var(--color-code-bg);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  box-shadow: var(--shadow-xl);
  font-family: var(--font-mono);
  color: var(--color-code-text);
  font-size: 0.9rem;
  line-height: 1.7;
  position: relative;
  border: 1px solid rgba(167, 139, 250, 0.2);
}
.code-card__chrome {
  display: flex;
  gap: 6px;
  margin-bottom: var(--space-4);
}
.code-card__chrome span { width: 12px; height: 12px; border-radius: 50%; background: #475569; }
.code-card__chrome span:nth-child(1) { background: #EF4444; }
.code-card__chrome span:nth-child(2) { background: #F59E0B; }
.code-card__chrome span:nth-child(3) { background: #10B981; }

/* ----------- Code blocks ----------- */
.code-block {
  position: relative;
  background: var(--color-code-bg);
  border-radius: var(--radius-md);
  margin: var(--space-5) 0;
  overflow: hidden;
  border: 1px solid var(--color-border);
}
.code-block__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-2) var(--space-4);
  background: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
.code-block__lang {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #94A3B8;
}
.code-block__copy {
  color: #94A3B8;
  font-size: 0.8rem;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}
.code-block__copy:hover { background: rgba(255, 255, 255, 0.08); color: var(--color-code-text); }
.code-block__copy.is-copied { color: var(--color-success); }
.code-block pre {
  margin: 0;
  padding: var(--space-4) var(--space-5);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--color-code-text);
}
.code-block code { color: inherit; background: transparent; padding: 0; border: 0; }

.tok-kw { color: var(--color-code-keyword); font-weight: 500; }
.tok-str { color: var(--color-code-string); }
.tok-num { color: var(--color-code-number); }
.tok-com { color: var(--color-code-comment); font-style: italic; }
.tok-fn { color: var(--color-code-fn); }

/* ----------- Code tabs ----------- */
.code-tabs {
  margin: var(--space-6) 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
}
.code-tabs__buttons {
  display: flex;
  background: var(--color-surface-2);
  border-bottom: 1px solid var(--color-border);
}
.code-tabs__btn {
  padding: var(--space-3) var(--space-5);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
  font-weight: 600;
}
.code-tabs__btn:hover { color: var(--color-text); }
.code-tabs__btn.is-active {
  color: var(--color-primary-dark);
  background: var(--color-surface);
  border-bottom-color: var(--color-primary);
}
[data-theme="dark"] .code-tabs__btn.is-active { color: var(--color-primary-light); }
.code-tabs__panel { display: none; }
.code-tabs__panel.is-active { display: block; }
.code-tabs__panel pre {
  margin: 0;
  padding: var(--space-4) var(--space-5);
  background: var(--color-code-bg);
  color: var(--color-code-text);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.65;
}

/* ----------- Callouts ----------- */
.callout {
  padding: var(--space-5);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-info);
  background: rgba(2, 132, 199, 0.06);
  margin: var(--space-6) 0;
  display: flex;
  gap: var(--space-3);
}
[data-theme="dark"] .callout { background: rgba(56, 189, 248, 0.08); }
.callout__icon { font-size: 1.25rem; line-height: 1; flex-shrink: 0; margin-top: 2px; }
.callout__body { flex: 1; }
.callout__body p:last-child { margin-bottom: 0; }
.callout__title {
  font-weight: 700;
  font-family: var(--font-display);
  margin-bottom: 4px;
  font-size: 1rem;
}
.callout--tip { border-color: var(--color-success); background: rgba(5, 150, 105, 0.06); }
[data-theme="dark"] .callout--tip { background: rgba(52, 211, 153, 0.08); }
.callout--warn { border-color: var(--color-warning); background: rgba(217, 119, 6, 0.08); }
[data-theme="dark"] .callout--warn { background: rgba(251, 191, 36, 0.08); }
.callout--danger { border-color: var(--color-danger); background: rgba(220, 38, 38, 0.06); }
[data-theme="dark"] .callout--danger { background: rgba(248, 113, 113, 0.08); }

/* ----------- FAQ ----------- */
.faq-list { display: flex; flex-direction: column; gap: var(--space-2); }
.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  overflow: hidden;
  transition: all var(--transition-fast);
}
.faq-item[open] { border-color: var(--color-primary-light); box-shadow: var(--shadow-sm); }
.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: var(--space-4) var(--space-5);
  font-weight: 600;
  font-family: var(--font-display);
  font-size: 1.05rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-3);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  flex-shrink: 0;
  width: 26px; height: 26px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-radius: 50%;
  transition: transform var(--transition-fast);
  font-weight: 400;
}
[data-theme="dark"] .faq-item summary::after { background: rgba(167, 139, 250, 0.2); }
.faq-item[open] summary::after { content: "−"; }
.faq-item__body { padding: 0 var(--space-5) var(--space-5); color: var(--color-text-muted); }
.faq-item__body p:first-child { margin-top: 0; }

/* ----------- Breadcrumbs ----------- */
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: center;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: var(--space-6) 0 var(--space-4);
  list-style: none;
  padding: 0;
}
.breadcrumbs li { display: inline-flex; align-items: center; gap: var(--space-2); }
.breadcrumbs li:not(:last-child)::after { content: "/"; color: var(--color-border-strong); }
.breadcrumbs a { color: var(--color-text-muted); }
.breadcrumbs a:hover { color: var(--color-primary); }
.breadcrumbs [aria-current="page"] { color: var(--color-text); font-weight: 500; }

/* ----------- TOC ----------- */
.toc {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  font-size: 0.92rem;
  box-shadow: var(--shadow-sm);
}
.toc__title {
  font-family: var(--font-display);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
  font-weight: 700;
}
.toc ul { list-style: none; padding: 0; margin: 0; }
.toc li { margin-bottom: var(--space-2); }
.toc li ul { padding-left: var(--space-4); margin-top: var(--space-2); }
.toc a {
  color: var(--color-text-muted);
  text-decoration: none;
  display: block;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  border-left: 2px solid transparent;
  transition: all var(--transition-fast);
}
.toc a:hover, .toc a.is-active {
  color: var(--color-primary-dark);
  background: var(--color-primary-soft);
  border-left-color: var(--color-primary);
}
[data-theme="dark"] .toc a:hover, [data-theme="dark"] .toc a.is-active { color: var(--color-primary-light); background: rgba(167,139,250,0.18); }

.article-layout {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: var(--space-12);
  margin-top: var(--space-8);
  align-items: start;
}
.article-layout__main { min-width: 0; }
.article-layout__sidebar { position: sticky; top: calc(var(--header-height) + var(--space-4)); }
@media (max-width: 1024px) {
  .article-layout { grid-template-columns: 1fr; }
  .article-layout__sidebar { position: static; }
}

article.prose { max-width: var(--article-max); }
article.prose p, article.prose ul, article.prose ol { font-size: 1.0625rem; }
article.prose ul, article.prose ol { margin-bottom: var(--space-5); }
article.prose ul li, article.prose ol li { margin-bottom: var(--space-2); }

/* ----------- Compare table ----------- */
.compare-table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-6) 0;
  font-size: 0.95rem;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  table-layout: fixed;
}
.compare-table th, .compare-table td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
  word-wrap: break-word;
  overflow-wrap: anywhere;
  hyphens: auto;
  vertical-align: top;
}
.compare-table thead { background: var(--gradient-soft); }
.compare-table thead th { font-family: var(--font-display); font-weight: 700; }
.compare-table tbody tr:nth-child(even) { background: var(--color-surface-2); }
.compare-table tbody tr:hover { background: var(--color-primary-soft); }
[data-theme="dark"] .compare-table tbody tr:hover { background: rgba(167,139,250,0.12); }
.compare-table td:first-child, .compare-table th:first-child { font-weight: 600; color: var(--color-text); width: 38%; }
.compare-table td:nth-child(2), .compare-table th:nth-child(2) { width: 31%; }
.compare-table td:nth-child(3), .compare-table th:nth-child(3) { width: 31%; }

/* ----------- Author bio ----------- */
.author-bio {
  display: flex;
  gap: var(--space-5);
  padding: var(--space-6);
  background: var(--gradient-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  margin: var(--space-12) 0;
  box-shadow: var(--shadow-sm);
}
.author-bio__avatar {
  width: 72px; height: 72px;
  border-radius: 50%;
  background: var(--gradient-hero);
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  box-shadow: var(--shadow-md);
}
.author-bio__name { font-size: 1.1rem; font-family: var(--font-display); font-weight: 700; margin: 0 0 4px; }
.author-bio__title { font-size: 0.875rem; color: var(--color-text-muted); margin-bottom: var(--space-2); }
.author-bio__desc { font-size: 0.95rem; color: var(--color-text-muted); margin: 0; }
@media (max-width: 600px) {
  .author-bio { flex-direction: column; }
}

/* ----------- Page meta ----------- */
.page-meta {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}
.page-meta__item { display: inline-flex; align-items: center; gap: 6px; }

/* ----------- Quiz ----------- */
.quiz {
  background: var(--gradient-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin: var(--space-8) 0;
  box-shadow: var(--shadow-sm);
}
.quiz__progress {
  height: 6px;
  background: var(--color-surface-2);
  border-radius: var(--radius-pill);
  overflow: hidden;
  margin-bottom: var(--space-5);
}
.quiz__progress-bar {
  height: 100%;
  background: var(--gradient-hero);
  width: 0%;
  transition: width var(--transition-base);
}
.quiz__question {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--space-5);
}
.quiz__options { display: flex; flex-direction: column; gap: var(--space-3); margin-bottom: var(--space-5); }
.quiz__option {
  display: block;
  padding: var(--space-3) var(--space-4);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  background: var(--color-surface);
  text-align: left;
  font-size: 0.95rem;
  transition: all var(--transition-fast);
  width: 100%;
  color: var(--color-text);
}
.quiz__option:hover { border-color: var(--color-primary); background: var(--color-primary-soft); }
.quiz__option.is-correct { border-color: var(--color-success); background: rgba(5, 150, 105, 0.1); color: var(--color-success); }
.quiz__option.is-wrong { border-color: var(--color-danger); background: rgba(220, 38, 38, 0.1); color: var(--color-danger); animation: shake 400ms ease; }
.quiz__option.is-disabled { cursor: default; opacity: 0.6; }
.quiz__feedback { padding: var(--space-3) var(--space-4); border-radius: var(--radius-md); margin-bottom: var(--space-4); font-size: 0.95rem; }
.quiz__feedback--correct { background: rgba(5, 150, 105, 0.1); color: var(--color-success); }
.quiz__feedback--wrong { background: rgba(220, 38, 38, 0.1); color: var(--color-danger); }
[data-theme="dark"] .quiz__feedback--correct { color: #6EE7B7; }
[data-theme="dark"] .quiz__feedback--wrong { color: #FCA5A5; }
.quiz__actions { display: flex; gap: var(--space-3); justify-content: space-between; align-items: center; flex-wrap: wrap; }
.quiz__score { font-size: 0.9rem; color: var(--color-text-muted); }

/* ----------- Pager ----------- */
.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin-top: var(--space-12);
}
.pager a {
  display: block;
  padding: var(--space-5);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: inherit;
  transition: all var(--transition-base);
}
.pager a:hover { border-color: var(--color-primary); transform: translateY(-2px); box-shadow: var(--shadow-md); text-decoration: none; }
.pager__label { font-size: 0.75rem; text-transform: uppercase; color: var(--color-text-muted); letter-spacing: 0.08em; }
.pager__title { font-family: var(--font-display); font-weight: 700; font-size: 1rem; margin-top: 4px; color: var(--color-text); }
.pager__next { text-align: right; }
@media (max-width: 600px) {
  .pager { grid-template-columns: 1fr; }
  .pager__next { text-align: left; }
}

/* ----------- Helpful ----------- */
.helpful {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
  margin: var(--space-8) 0;
}
.helpful__btns { display: flex; gap: var(--space-2); }
.helpful__btn {
  padding: 6px 12px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.helpful__btn:hover { border-color: var(--color-primary); background: var(--color-primary-soft); }
.helpful__btn.is-active { border-color: var(--color-primary); background: var(--color-primary); color: white; }

/* ----------- CTA ----------- */
.cta-banner {
  background: var(--gradient-hero);
  color: white;
  padding: var(--space-12) var(--space-8);
  border-radius: var(--radius-xl);
  text-align: center;
  margin: var(--space-12) 0;
  position: relative;
  overflow: hidden;
}
.cta-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--gradient-mesh);
  opacity: 0.3;
}
.cta-banner > * { position: relative; z-index: 1; }
.cta-banner h2 { color: white; margin-top: 0; }
.cta-banner p { font-size: 1.1rem; opacity: 0.95; margin-bottom: var(--space-6); }
.cta-banner .btn { background: white; color: var(--color-primary-dark); }
.cta-banner .btn:hover { background: rgba(255, 255, 255, 0.95); color: var(--color-primary-dark); }

/* ----------- Glossary ----------- */
.glossary-term {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  margin-bottom: var(--space-3);
  scroll-margin-top: calc(var(--header-height) + var(--space-4));
}
.glossary-term__head { display: flex; align-items: center; justify-content: space-between; gap: var(--space-3); flex-wrap: wrap; }
.glossary-term__name { font-family: var(--font-display); font-weight: 700; font-size: 1.2rem; margin: 0; }
.glossary-term__def { font-size: 1rem; color: var(--color-text); margin: var(--space-2) 0; }
.glossary-term__detail { font-size: 0.95rem; color: var(--color-text-muted); }

/* ----------- Stats ----------- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-4);
  margin: var(--space-8) 0;
}
.stat-card {
  padding: var(--space-5);
  background: var(--gradient-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-align: center;
  box-shadow: var(--shadow-sm);
}
.stat-card__value {
  font-family: var(--font-display);
  font-size: 2.25rem;
  font-weight: 800;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.stat-card__label { font-size: 0.85rem; color: var(--color-text-muted); text-transform: uppercase; letter-spacing: 0.05em; }

/* ----------- Diagrams ----------- */
.diagram {
  background: var(--gradient-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin: var(--space-6) 0;
  text-align: center;
  box-shadow: var(--shadow-sm);
}
.diagram svg { max-width: 100%; height: auto; }
.diagram__caption { margin-top: var(--space-3); font-size: 0.875rem; color: var(--color-text-muted); font-style: italic; }

/* ----------- Playground ----------- */
.playground {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin: var(--space-6) 0;
  min-height: 400px;
}
@media (max-width: 800px) {
  .playground { grid-template-columns: 1fr; }
}
.playground__editor, .playground__output {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.playground__head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--color-surface-2);
  padding: var(--space-2) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  font-size: 0.85rem;
  font-weight: 600;
}
.playground__head select {
  padding: 4px 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  font-size: 0.85rem;
  color: var(--color-text);
}
.playground textarea {
  width: 100%; flex: 1; min-height: 320px;
  padding: var(--space-4);
  border: none;
  background: var(--color-code-bg);
  color: var(--color-code-text);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.6;
  resize: vertical;
}
.playground textarea:focus { outline: none; box-shadow: inset 0 0 0 2px var(--color-primary); }
.playground__output-pane {
  flex: 1;
  background: var(--color-bg);
  padding: var(--space-4);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  white-space: pre-wrap;
  overflow: auto;
  color: var(--color-text);
  min-height: 320px;
}
.playground__output-pane.is-error { color: var(--color-danger); }
.playground__actions { display: flex; gap: var(--space-2); }

/* ----------- Kids ----------- */
.kids-tone p { font-size: 1.1rem; line-height: 1.8; }
.kids-tone .callout { font-size: 1.05rem; border-radius: var(--radius-lg); }
.kids-tone .hero { background: linear-gradient(135deg, #FED7AA 0%, #FBCFE8 50%, #C7D2FE 100%); }

/* ----------- Reveal ----------- */
.reveal { opacity: 0; transform: translateY(20px); transition: all 600ms cubic-bezier(0.2, 0.8, 0.2, 1); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }

/* ----------- TL;DR card ----------- */
.tldr-card {
  background: var(--gradient-soft);
  border: 1.5px solid var(--color-primary-light);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  margin: var(--space-6) 0;
  position: relative;
  box-shadow: var(--shadow-sm);
}
[data-theme="dark"] .tldr-card {
  background: linear-gradient(135deg, rgba(167, 139, 250, 0.12) 0%, rgba(244, 114, 182, 0.08) 100%);
  border-color: rgba(167, 139, 250, 0.3);
}
.tldr-card__pill {
  display: inline-block;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  background: var(--gradient-hero);
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: var(--space-3);
  box-shadow: var(--shadow-sm);
}
.tldr-card__one { font-size: 1.15rem; line-height: 1.5; margin-bottom: var(--space-2); color: var(--color-text); }
.tldr-card__analogy, .tldr-card__remember { font-size: 0.95rem; margin-bottom: var(--space-2); color: var(--color-text); }
.tldr-card p:last-child { margin-bottom: 0; }

/* ----------- Real world cards ----------- */
.real-world-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-4);
  margin: var(--space-5) 0;
}
.real-world-card {
  padding: var(--space-5);
  background: var(--gradient-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-accent);
  box-shadow: var(--shadow-sm);
}
.real-world-card h4 {
  margin-top: 0;
  margin-bottom: var(--space-2);
  color: var(--color-accent-dark);
  font-size: 1rem;
}
[data-theme="dark"] .real-world-card h4 { color: var(--color-accent); }
.real-world-card p { margin: 0; font-size: 0.95rem; color: var(--color-text-muted); }

/* ----------- Bug cards ----------- */
.bug-card {
  margin: var(--space-8) 0;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--gradient-card);
  box-shadow: var(--shadow-sm);
}
.bug-card__head {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  background: linear-gradient(90deg, rgba(220, 38, 38, 0.08) 0%, transparent 100%);
  border-bottom: 1px solid var(--color-border);
}
.bug-card__head h3 { margin: 0; font-size: 1.15rem; }
.bug-card__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 36px; height: 36px;
  padding: 0 8px;
  background: var(--color-danger);
  color: white;
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.85rem;
}
.bug-card .code-block { margin: var(--space-4); }
.bug-card .callout { margin: var(--space-4); }

/* ----------- Bee illustration helpers ----------- */
.bee-card {
  display: flex;
  gap: 1.25rem;
  align-items: center;
  padding: 1rem 1.25rem;
  background: var(--color-surface-2);
  border-radius: var(--radius-lg);
  margin: 1.25rem 0;
  border: 1px solid var(--color-border);
}
.bee-card img { width: 64px; height: 64px; flex-shrink: 0; animation: float 4s ease-in-out infinite; }
.bee-card__text { font-size: 0.95rem; color: var(--color-text-muted); margin: 0; }
.bee-card__text strong { color: var(--color-text); font-family: var(--font-display); }

/* ----------- Related Reading sidebar ----------- */
.related-reading {
  margin-top: var(--space-5);
  padding: var(--space-5);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.92rem;
  box-shadow: var(--shadow-sm);
}
.rr-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.rr-list li { margin-bottom: 4px; }
.rr-list a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: all var(--transition-fast);
  font-size: 0.9rem;
}
.rr-list a:hover {
  background: var(--color-primary-soft);
  color: var(--color-primary-dark);
}
[data-theme="dark"] .rr-list a:hover { background: rgba(167, 139, 250, 0.14); color: var(--color-primary-light); }
.rr-icon { font-size: 1.05rem; flex-shrink: 0; line-height: 1; }

/* ----------- Decorative section divider ----------- */
.section-divider {
  height: 60px;
  background: var(--gradient-hero);
  -webkit-mask: linear-gradient(180deg, transparent, black 40%, black 60%, transparent);
  mask: linear-gradient(180deg, transparent, black 40%, black 60%, transparent);
  opacity: 0.15;
  margin: var(--space-12) 0;
}

/* ----------- Language switcher (footer dropdown) ----------- */
.lang-switcher {
  position: relative;
  margin-left: auto;
  font-family: var(--font-body);
}
.lang-switcher__btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  border-radius: var(--radius-md);
  padding: 8px 14px;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.18s ease, border-color 0.18s ease;
  min-height: 40px;
}
.lang-switcher__btn:hover,
.lang-switcher__btn:focus-visible {
  background: rgba(255, 255, 255, 0.10);
  border-color: var(--color-primary-light);
  outline: none;
}
.lang-switcher__btn svg { flex-shrink: 0; opacity: 0.8; }
.lang-switcher__btn span { white-space: nowrap; }
.lang-switcher__menu {
  position: absolute;
  bottom: calc(100% + 8px);
  right: 0;
  min-width: 220px;
  max-height: 360px;
  overflow-y: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  list-style: none;
  margin: 0;
  padding: 6px;
  display: none;
  z-index: 60;
}
.lang-switcher.is-open .lang-switcher__menu { display: block; }
.lang-switcher__menu li { margin: 0; }
.lang-switcher__menu a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 12px;
  text-decoration: none;
  color: var(--color-text);
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.15s ease;
}
.lang-switcher__menu a:hover,
.lang-switcher__menu a:focus-visible {
  background: var(--color-surface-2);
  outline: none;
}
.lang-switcher__menu li[aria-current="true"] a {
  background: var(--color-primary-soft);
  color: var(--color-primary-dark);
  font-weight: 600;
}
[data-theme="dark"] .lang-switcher__menu li[aria-current="true"] a {
  background: rgba(167, 139, 250, 0.18);
  color: var(--color-primary-light);
}
.lang-switcher__code {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--color-text-soft);
  background: var(--color-surface-2);
  padding: 2px 6px;
  border-radius: 4px;
}
[data-theme="dark"] .lang-switcher__code {
  background: rgba(255, 255, 255, 0.06);
}

/* Footer bottom row: stack language switcher cleanly with copyright */
.site-footer__bottom { gap: var(--space-3); flex-wrap: wrap; }

@media (max-width: 640px) {
  .lang-switcher { margin-left: 0; width: 100%; }
  .lang-switcher__btn { width: 100%; justify-content: space-between; min-height: 44px; }
  .lang-switcher__menu { left: 0; right: 0; min-width: 0; }
}