/* === Anthropic Design System — Core CSS ===
 * Last verified: 2026-04-19
 * Docs: ../references/design-tokens.md
 */

/* ---------- Section A: Tokens ---------- */
:root {
  /* Colors */
  --anth-bg: #faf9f5;
  --anth-bg-subtle: #f0ede3;
  --anth-text: #141413;
  --anth-text-secondary: #6b6a5f;
  --anth-orange: #d97757;
  --anth-orange-hover: #c56544;
  --anth-blue: #6a9bcc;
  --anth-green: #788c5d;
  --anth-mid-gray: #b0aea5;
  --anth-light-gray: #e8e6dc;
  --anth-danger: #a14238;

  /* Fonts */
  --font-heading: "Poppins", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Lora", Georgia, "Times New Roman", serif;
  --font-mono: "JetBrains Mono", ui-monospace, Menlo, monospace;

  /* Spacing (4px grid) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 80px;
  --space-10: 120px;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 9999px;

  /* Shadows */
  --shadow-card: 0 2px 12px rgba(20, 20, 19, 0.05);
  --shadow-pop: 0 10px 40px rgba(20, 20, 19, 0.08);

  /* Motion */
  --ease-anth: cubic-bezier(0.25, 1, 0.5, 1);
  --duration-sm: 240ms;
  --duration-md: 400ms;
  --duration-lg: 700ms;
}

/* ---------- Section B: Reset ---------- */
* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-body);
  font-size: 18px;
  line-height: 1.65;
  color: var(--anth-text);
  background: var(--anth-bg);
  -webkit-font-smoothing: antialiased;
}

/* ---------- Section C: Typography ---------- */
h1,
h2,
h3,
h4,
h5 {
  font-family: var(--font-heading);
  margin: 0;
  font-weight: 600;
}

h1 {
  font-size: 56px;
  line-height: 1.1;
}

h2 {
  font-size: 40px;
  line-height: 1.15;
}

h3 {
  font-size: 24px;
  line-height: 1.3;
  font-weight: 500;
}

h4 {
  font-size: 20px;
  line-height: 1.4;
}

p {
  margin: 0 0 var(--space-4);
}

.anth-caption {
  font-size: 13px;
  line-height: 1.4;
  color: var(--anth-text-secondary);
}

/* ---------- Section D: Link & Button (Anthropic uses filled pills as primary CTA) ---------- */
.anth-button {
  display: inline-block;
  padding: 12px 24px;
  border-radius: var(--radius-pill);
  background: var(--anth-orange);
  color: #ffffff;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  border: 0;
  cursor: pointer;
  transition: background var(--duration-sm) var(--ease-anth);
}

.anth-button:hover {
  background: var(--anth-orange-hover);
}

.anth-button--dark {
  background: var(--anth-text);
  color: var(--anth-bg);
}

.anth-button--ghost {
  background: transparent;
  color: var(--anth-text);
  border: 1px solid var(--anth-text);
}

.anth-link {
  color: var(--anth-orange);
  text-decoration: underline;
  text-underline-offset: 0.2em;
  transition: color var(--duration-sm);
}

.anth-link:hover {
  color: var(--anth-orange-hover);
}

.anth-link::after {
  content: " \2192";
}

.anth-link--no-arrow::after {
  content: none;
}

/* ---------- Section E: Layout ---------- */
.anth-container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

.anth-container--narrow {
  max-width: 720px;
}

.anth-container--wide {
  max-width: 1200px;
}

.anth-section {
  padding-block: var(--space-8);
}

.anth-section--subtle {
  background: var(--anth-bg-subtle);
}

.anth-card {
  background: #ffffff;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  padding: var(--space-5);
}

.anth-hero {
  text-align: center;
  padding-block: var(--space-10);
}

/* ---------- Section F: Stat ---------- */
.anth-stat {
  text-align: center;
}

.anth-stat-number {
  display: block;
  font-family: var(--font-heading);
  font-size: 64px;
  line-height: 1;
  font-weight: 700;
  color: var(--anth-text);
}

.anth-stat-label {
  display: block;
  font-family: var(--font-body);
  font-size: 14px;
  color: var(--anth-text-secondary);
  margin-top: var(--space-3);
}

/* ---------- Section G: Nav ---------- */
.anth-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 64px;
  background: var(--anth-bg);
  border-bottom: 1px solid var(--anth-light-gray);
}

.anth-nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
}

.anth-nav a {
  color: var(--anth-text);
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  margin-right: var(--space-5);
}

/* ---------- Section H: Footer ---------- */
.anth-footer {
  background: var(--anth-bg-subtle);
  padding-block: var(--space-7);
  font-size: 13px;
  color: var(--anth-text-secondary);
}

.anth-footer-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: var(--space-6);
}

.anth-footer-group h5 {
  font-family: var(--font-heading);
  font-size: 13px;
  color: var(--anth-text);
  margin-bottom: var(--space-3);
}

.anth-footer-group a {
  display: block;
  color: var(--anth-text-secondary);
  text-decoration: none;
  margin-bottom: var(--space-2);
}

.anth-footer-legal {
  max-width: 1200px;
  margin: var(--space-6) auto 0;
  padding: var(--space-5) 24px 0;
  border-top: 1px solid var(--anth-light-gray);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.anth-social {
  display: flex;
  gap: var(--space-3);
}

/* ---------- Section I: Badge / Quote / Divider / Banner ---------- */
.anth-badge {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 12px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  background: var(--anth-light-gray);
  color: var(--anth-text);
}

.anth-quote {
  font-family: var(--font-body);
  font-style: italic;
  font-size: 22px;
  line-height: 1.55;
  padding-left: var(--space-5);
  border-left: 3px solid var(--anth-orange);
  max-width: 680px;
  margin: var(--space-6) 0;
}

.anth-quote-cite {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-top: var(--space-4);
  font-size: 14px;
  font-style: normal;
  font-family: var(--font-heading);
}

.anth-quote-cite img {
  height: 20px;
  width: auto;
}

.anth-divider {
  border: 0;
  height: 1px;
  background: var(--anth-light-gray);
  margin: var(--space-8) 0;
}

.anth-banner {
  padding: var(--space-3) var(--space-5);
  background: var(--anth-bg-subtle);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: 14px;
}

/* ---------- Section J: Form controls ---------- */
.anth-input,
.anth-select,
.anth-textarea {
  width: 100%;
  background: var(--anth-bg);
  border: 1px solid var(--anth-light-gray);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  font-family: var(--font-body);
  font-size: 15px;
  color: var(--anth-text);
}

.anth-input:focus,
.anth-select:focus,
.anth-textarea:focus {
  outline: 2px solid var(--anth-orange);
  outline-offset: 0;
  border-color: transparent;
}

.anth-radio,
.anth-checkbox {
  accent-color: var(--anth-orange);
  width: 18px;
  height: 18px;
}

.anth-label {
  font-family: var(--font-heading);
  font-size: 14px;
  color: var(--anth-text);
  margin-bottom: var(--space-2);
  display: block;
}

/* ---------- Section K: Tabs / Carousel / Video / Details ---------- */
.anth-tabs {
  display: flex;
  gap: var(--space-5);
  border-bottom: 1px solid var(--anth-light-gray);
}

.anth-tab {
  background: transparent;
  border: 0;
  padding: var(--space-3) 0;
  font-family: var(--font-heading);
  font-size: 14px;
  color: var(--anth-text-secondary);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: color var(--duration-sm), border-bottom-color var(--duration-sm);
}

.anth-tab.is-active {
  color: var(--anth-text);
  border-bottom-color: var(--anth-orange);
}

.anth-carousel {
  position: relative;
  overflow: hidden;
}

.anth-carousel-viewport {
  display: flex;
  transition: transform var(--duration-md) var(--ease-anth);
}

.anth-carousel-counter {
  font-family: var(--font-heading);
  font-size: 13px;
  color: var(--anth-text-secondary);
}

.anth-video {
  width: 100%;
  border-radius: var(--radius-md);
}

.anth-details {
  background: var(--anth-bg-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  margin: var(--space-3) 0;
}

.anth-details summary {
  cursor: pointer;
  font-family: var(--font-heading);
  font-weight: 500;
  list-style: none;
  display: flex;
  justify-content: space-between;
}

.anth-details summary::after {
  content: '\25B8';
  transition: transform var(--duration-sm);
}

.anth-details[open] summary::after {
  transform: rotate(90deg);
}

/* ---------- Section L: Admonition / Code / Logo wall / Breadcrumbs / Reveal / Table ---------- */
.anth-admonition {
  background: var(--anth-bg-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  margin: var(--space-5) 0;
}

.anth-admonition h5 {
  font-family: var(--font-heading);
  font-weight: 500;
  margin: 0 0 var(--space-2);
  color: var(--anth-blue);
}

.anth-admonition--warning h5 {
  color: var(--anth-orange);
}

.anth-admonition--success h5 {
  color: var(--anth-green);
}

.anth-admonition--danger h5 {
  color: var(--anth-danger);
}

.anth-code,
pre.anth-code {
  font-family: var(--font-mono);
  font-size: 14px;
  background: var(--anth-bg-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-6);
  overflow-x: auto;
}

code {
  font-family: var(--font-mono);
  font-size: 0.93em;
  background: var(--anth-bg-subtle);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

kbd {
  font-family: var(--font-mono);
  font-size: 12px;
  background: var(--anth-bg);
  border: 1px solid var(--anth-light-gray);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

mark {
  background: rgba(217, 119, 87, 0.2);
}

.anth-logo-wall {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: var(--space-6);
  align-items: center;
}

.anth-logo-wall img {
  max-height: 32px;
  width: auto;
  filter: grayscale(1) opacity(0.6);
  transition: filter var(--duration-sm);
}

.anth-logo-wall img:hover {
  filter: none;
}

.anth-breadcrumbs {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-size: 13px;
  color: var(--anth-text-secondary);
  font-family: var(--font-heading);
}

.anth-breadcrumbs li::after {
  content: '\203A';
  margin-left: var(--space-2);
  color: var(--anth-mid-gray);
}

.anth-breadcrumbs li:last-child::after {
  content: none;
}

.anth-breadcrumbs a {
  color: inherit;
  text-decoration: none;
}

.anth-breadcrumbs a:hover {
  text-decoration: underline;
}

.anth-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-body);
  font-size: 15px;
}

.anth-table th {
  text-align: left;
  padding: 12px 16px;
  background: var(--anth-bg-subtle);
  font-family: var(--font-heading);
  font-weight: 500;
}

.anth-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--anth-light-gray);
}

.anth-table tr:hover td {
  background: var(--anth-bg-subtle);
}

.anth-table .check {
  color: var(--anth-green);
}

.anth-table .cross {
  color: var(--anth-mid-gray);
}

.anth-reveal {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity var(--duration-lg) var(--ease-anth),
    transform var(--duration-lg) var(--ease-anth);
}

.anth-reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Section M: Responsive + a11y ---------- */
@media (max-width: 768px) {
  h1 {
    font-size: 36px;
  }
  h2 {
    font-size: 28px;
  }
  .anth-footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .anth-logo-wall {
    grid-template-columns: repeat(3, 1fr);
  }
  .anth-section {
    padding-block: var(--space-7);
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  h1 {
    font-size: 48px;
  }
  .anth-footer-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.anth-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

:focus-visible {
  outline: 2px solid var(--anth-orange);
  outline-offset: 2px;
  border-radius: 2px;
}

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