/* ==========================================================================
   httpbin — shared design system
   Palette, type scale, spacing, motion tokens + the site chrome components
   every page reuses verbatim (header/nav, footer, container, buttons, cards).
   Mobile-first: base rules target small screens, min-width queries add on.
   ========================================================================== */

@import url("https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;600;700&family=Source+Code+Pro:wght@300;400;600&family=Titillium+Web:wght@400;600;700&display=swap");

/* --------------------------------------------------------------------------
   1. Design tokens
   -------------------------------------------------------------------------- */
:root {
  /* Brand */
  --color-primary: rgb(59, 65, 81);
  --color-primary-strong: rgb(38, 43, 55);
  --color-primary-contrast: rgb(255, 255, 255);
  --color-secondary: rgb(73, 204, 144);
  --color-secondary-strong: rgb(56, 178, 122);
  --color-accent: rgb(255, 255, 0);
  --color-accent-strong: rgb(221, 221, 0);

  /* Semantic */
  --color-success: rgb(73, 204, 144);
  --color-success-strong: rgb(56, 178, 122);
  --color-danger: rgb(249, 62, 62);
  --color-danger-strong: rgb(214, 45, 45);

  /* Neutrals */
  --color-black: rgb(0, 0, 0);
  --color-ink: rgb(17, 17, 17);
  --color-gray-900: rgb(51, 51, 51);
  --color-gray-700: rgb(85, 85, 85);
  --color-gray-600: rgb(119, 119, 119);
  --color-gray-500: rgb(153, 153, 153);
  --color-gray-400: rgb(170, 170, 170);
  --color-gray-300: rgb(204, 204, 204);
  --color-gray-200: rgb(238, 238, 238);
  --color-gray-100: rgb(244, 244, 244);
  --color-white: rgb(255, 255, 255);

  --color-overlay-90: rgba(255, 255, 255, 0.9);
  --color-overlay-80: rgba(255, 255, 255, 0.8);
  --color-overlay-70: rgba(255, 255, 255, 0.7);

  /* Semantic aliases */
  --color-bg: var(--color-gray-100);
  --color-surface: var(--color-white);
  --color-surface-alt: var(--color-gray-200);
  --color-text: var(--color-primary);
  --color-text-strong: var(--color-ink);
  --color-text-muted: var(--color-gray-600);
  --color-text-inverse: var(--color-overlay-80);
  --color-border: var(--color-gray-300);
  --color-border-soft: var(--color-gray-200);
  --color-link: var(--color-primary);
  --color-link-hover: var(--color-ink);
  --color-highlight: var(--color-accent);
  --color-console: var(--color-ink);
  --color-console-text: var(--color-gray-200);

  --color-header-bg: var(--color-overlay-90);
  --color-header-border: var(--color-border-soft);
  --color-footer-bg: var(--color-primary);
  --color-footer-text: var(--color-overlay-70);
  --color-footer-heading: var(--color-white);
  --color-footer-link: var(--color-overlay-80);
  --color-footer-link-hover: var(--color-accent);
  --color-footer-border: rgba(255, 255, 255, 0.2);

  /* Typography */
  --font-sans: "Open Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-display: "Titillium Web", "Open Sans", -apple-system, sans-serif;
  --font-mono: "Source Code Pro", Consolas, "SF Mono", Menlo, monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.375rem;
  --text-2xl: 1.75rem;
  --text-3xl: clamp(1.875rem, 2vw + 1.25rem, 2.375rem);
  --text-4xl: clamp(2.25rem, 3vw + 1.25rem, 3.25rem);

  --leading-tight: 1.15;
  --leading-snug: 1.35;
  --leading-normal: 1.6;

  --weight-regular: 400;
  --weight-semibold: 600;
  --weight-bold: 700;

  --tracking-tight: -0.015em;
  --tracking-wide: 0.04em;

  /* Spacing (4px base) */
  --space-0: 0;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  /* Radius */
  --radius-sm: 3px;
  --radius-md: 4px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-full: 999px;

  /* Elevation */
  --shadow-sm: 0 1px 2px rgba(17, 17, 17, 0.06);
  --shadow-md: 0 2px 8px rgba(17, 17, 17, 0.08), 0 1px 2px rgba(17, 17, 17, 0.06);
  --shadow-lg: 0 12px 32px rgba(17, 17, 17, 0.12), 0 2px 8px rgba(17, 17, 17, 0.06);
  --shadow-focus: 0 0 0 3px rgba(59, 65, 81, 0.25);

  /* Motion */
  --duration-instant: 100ms;
  --duration-fast: 150ms;
  --duration-base: 250ms;
  --duration-slow: 450ms;
  --duration-reveal: 600ms;
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-shake: cubic-bezier(0.36, 0.07, 0.19, 0.97);

  /* Layout */
  --container-max: 72rem;
  --container-wide: 90rem;
  --container-narrow: 44rem;
  --gutter: var(--space-4);
  --header-height: 4rem;
  --border-width: 1px;
}

/* --------------------------------------------------------------------------
   2. Base / reset
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-display);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--color-text-strong);
}

h1 { font-size: var(--text-4xl); font-weight: var(--weight-bold); }
h2 { font-size: var(--text-3xl); font-weight: var(--weight-semibold); }
h3 { font-size: var(--text-2xl); font-weight: var(--weight-semibold); }
h4 { font-size: var(--text-xl); font-weight: var(--weight-semibold); }
h5 { font-size: var(--text-lg); font-weight: var(--weight-semibold); }
h6 { font-size: var(--text-base); font-weight: var(--weight-semibold); }

p, ul, ol, dl, figure, pre, table {
  margin: 0 0 var(--space-4);
}

ul, ol {
  padding-left: var(--space-5);
}

a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color var(--duration-fast) var(--ease-out);
}

a:hover {
  color: var(--color-link-hover);
}

img, svg, video {
  max-width: 100%;
  height: auto;
  display: block;
}

code, kbd, samp, pre {
  font-family: var(--font-mono);
  font-size: 0.875em;
}

code {
  background: var(--color-gray-200);
  color: var(--color-ink);
  padding: 0.125em 0.375em;
  border-radius: var(--radius-sm);
}

pre {
  background: var(--color-console);
  color: var(--color-console-text);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  overflow-x: auto;
  line-height: var(--leading-snug);
}

pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  border-radius: 0;
  font-size: var(--text-sm);
}

kbd {
  background: var(--color-white);
  border: var(--border-width) solid var(--color-border);
  border-bottom-width: 2px;
  border-radius: var(--radius-sm);
  padding: 0.125em 0.4em;
  font-size: var(--text-xs);
  color: var(--color-gray-700);
}

mark {
  background: var(--color-highlight);
  color: var(--color-ink);
  padding: 0 0.15em;
}

hr {
  border: 0;
  border-top: var(--border-width) solid var(--color-border);
  margin: var(--space-8) 0;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

::selection {
  background: var(--color-accent);
  color: var(--color-ink);
}

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

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* --------------------------------------------------------------------------
   3. Layout helpers
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--wide {
  max-width: var(--container-wide);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.section {
  padding-block: var(--space-12);
}

@media (min-width: 768px) {
  .section {
    padding-block: var(--space-20);
  }
}

.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-auto {
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
}

.grid-cols-2,
.grid-cols-3,
.grid-cols-4 {
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .grid-cols-3 {
    grid-template-columns: repeat(3, 1fr);
  }

  .grid-cols-4 {
    grid-template-columns: repeat(4, 1fr);
  }
}

.stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.stack--sm { gap: var(--space-2); }
.stack--lg { gap: var(--space-8); }

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.cluster--between {
  justify-content: space-between;
}

.cluster--end {
  justify-content: flex-end;
}

.text-center { text-align: center; }
.text-muted { color: var(--color-text-muted); }
.text-sm { font-size: var(--text-sm); }
.text-xs { font-size: var(--text-xs); }

.lead {
  font-size: var(--text-lg);
  color: var(--color-gray-700);
  line-height: var(--leading-normal);
}

@media (min-width: 768px) {
  .lead {
    font-size: var(--text-xl);
  }
}

/* --------------------------------------------------------------------------
   4. Site header / navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-header-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: var(--border-width) solid var(--color-header-border);
}

.nav-toggle-input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
  pointer-events: none;
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  min-height: var(--header-height);
  position: relative;
}

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-text-strong);
  text-decoration: none;
}

.site-brand:hover {
  color: var(--color-primary);
}

.site-brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  background: var(--color-primary);
  color: var(--color-accent);
  border-radius: var(--radius-md);
  padding: 0.2rem 0.4rem;
  line-height: 1;
}

.site-brand-dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: var(--radius-full);
  background: var(--color-success);
  box-shadow: 0 0 0 3px rgba(73, 204, 144, 0.25);
}

.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 2.5rem;
  height: 2.5rem;
  padding: var(--space-2);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  transition: transform var(--duration-base) var(--ease-out),
              opacity var(--duration-fast) var(--ease-out);
}

.nav-toggle-input:checked ~ .site-header-inner .nav-toggle-bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle-input:checked ~ .site-header-inner .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle-input:checked ~ .site-header-inner .nav-toggle-bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.nav-toggle-input:focus-visible ~ .site-header-inner .nav-toggle {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.site-nav {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--color-surface);
  border-bottom: var(--border-width) solid var(--color-border);
  box-shadow: var(--shadow-lg);
  padding: var(--space-4);
  animation: scaleUp var(--duration-base) var(--ease-out) both;
}

.nav-toggle-input:checked ~ .site-header-inner .site-nav {
  display: block;
}

.site-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.site-nav-link {
  display: block;
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  text-decoration: none;
  color: var(--color-text);
  transition: background-color var(--duration-fast) var(--ease-out),
              color var(--duration-fast) var(--ease-out);
}

.site-nav-link:hover,
.site-nav-link:focus-visible {
  background: var(--color-gray-200);
  color: var(--color-link-hover);
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }

  .site-nav {
    display: block;
    position: static;
    background: transparent;
    border: 0;
    box-shadow: none;
    padding: 0;
    animation: none;
  }

  .site-nav-list {
    flex-direction: row;
    align-items: center;
    gap: var(--space-1);
  }

  .site-nav-link {
    padding: var(--space-2) var(--space-3);
  }
}

/* --------------------------------------------------------------------------
   5. Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.625rem 1.25rem;
  border: var(--border-width) solid transparent;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  line-height: 1.25;
  text-decoration: none;
  cursor: pointer;
  user-select: none;
  white-space: nowrap;
  transition: background-color var(--duration-fast) var(--ease-out),
              border-color var(--duration-fast) var(--ease-out),
              color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out),
              transform var(--duration-fast) var(--ease-out);
}

.btn:hover {
  text-decoration: none;
}

.btn:active {
  transform: translateY(1px);
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  box-shadow: var(--shadow-focus);
}

.btn[disabled],
.btn[aria-disabled="true"] {
  opacity: 0.55;
  cursor: not-allowed;
  transform: none;
}

.btn-primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-contrast);
}

.btn-primary:hover {
  background: var(--color-primary-strong);
  border-color: var(--color-primary-strong);
  color: var(--color-primary-contrast);
}

.btn-secondary {
  background: var(--color-surface);
  border-color: var(--color-border);
  color: var(--color-text);
}

.btn-secondary:hover {
  background: var(--color-gray-100);
  border-color: var(--color-gray-400);
  color: var(--color-text-strong);
}

.btn-accent {
  background: var(--color-accent);
  border-color: var(--color-accent-strong);
  color: var(--color-ink);
}

.btn-accent:hover {
  background: var(--color-accent-strong);
  border-color: var(--color-accent-strong);
  color: var(--color-ink);
}

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--color-text);
}

.btn-ghost:hover {
  background: var(--color-gray-200);
  color: var(--color-text-strong);
}

.btn-success {
  background: var(--color-success);
  border-color: var(--color-success-strong);
  color: var(--color-ink);
}

.btn-success:hover {
  background: var(--color-success-strong);
  border-color: var(--color-success-strong);
  color: var(--color-ink);
}

.btn-danger {
  background: var(--color-danger);
  border-color: var(--color-danger-strong);
  color: var(--color-white);
}

.btn-danger:hover {
  background: var(--color-danger-strong);
  border-color: var(--color-danger-strong);
  color: var(--color-white);
}

.btn-sm {
  padding: 0.375rem 0.75rem;
  font-size: var(--text-xs);
}

.btn-lg {
  padding: 0.875rem 1.75rem;
  font-size: var(--text-base);
}

.btn-block {
  display: flex;
  width: 100%;
}

/* --------------------------------------------------------------------------
   6. Cards, badges, console surfaces
   -------------------------------------------------------------------------- */
.card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  background: var(--color-surface);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--duration-base) var(--ease-out),
              border-color var(--duration-base) var(--ease-out),
              transform var(--duration-base) var(--ease-out);
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-gray-400);
  transform: translateY(-2px);
}

.card-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  color: var(--color-text-strong);
}

.card-text {
  margin: 0;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.card-link {
  margin-top: auto;
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  text-decoration: none;
}

.card-link:hover {
  text-decoration: underline;
}

.card--flat:hover {
  transform: none;
  box-shadow: var(--shadow-sm);
}

.card--console {
  background: var(--color-console);
  border-color: var(--color-console);
  color: var(--color-console-text);
}

.card--console .card-title {
  color: var(--color-white);
}

.card--console .card-text {
  color: var(--color-overlay-70);
}

.card--console pre {
  background: rgba(255, 255, 255, 0.06);
  margin-bottom: 0;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 0.125rem 0.5rem;
  border-radius: var(--radius-full);
  border: var(--border-width) solid var(--color-border);
  background: var(--color-gray-200);
  color: var(--color-gray-900);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
}

.badge--success {
  background: rgba(73, 204, 144, 0.15);
  border-color: var(--color-success);
  color: var(--color-success-strong);
}

.badge--danger {
  background: rgba(249, 62, 62, 0.12);
  border-color: var(--color-danger);
  color: var(--color-danger-strong);
}

.badge--accent {
  background: var(--color-highlight);
  border-color: var(--color-accent-strong);
  color: var(--color-ink);
}

.method-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 4.25rem;
  padding: 0.125rem 0.5rem;
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
}

.method-chip--get { background: var(--color-success); color: var(--color-ink); }
.method-chip--post { background: var(--color-primary); color: var(--color-white); }
.method-chip--put,
.method-chip--patch { background: var(--color-gray-700); color: var(--color-white); }
.method-chip--delete { background: var(--color-danger); color: var(--color-white); }
.method-chip--head,
.method-chip--options { background: var(--color-gray-600); color: var(--color-white); }

.console {
  background: var(--color-console);
  color: var(--color-console-text);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  overflow-x: auto;
}

/* --------------------------------------------------------------------------
   7. Forms (playground / try-it)
   -------------------------------------------------------------------------- */
.field {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.field-label {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-text-strong);
}

.input,
.select,
.textarea {
  width: 100%;
  padding: 0.5rem 0.75rem;
  background: var(--color-surface);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-strong);
  transition: border-color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out);
}

.input:focus,
.select:focus,
.textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-focus);
}

.textarea {
  min-height: 8rem;
  resize: vertical;
}

/* --------------------------------------------------------------------------
   8. Motion — keyframes + reusable classes
   -------------------------------------------------------------------------- */
@keyframes rotation {
  from { transform: rotate(0turn); }
  to { transform: rotate(1turn); }
}

@keyframes blinker {
  50% { opacity: 0; }
}

@keyframes shake {
  10%, 90% { transform: translate3d(-1px, 0, 0); }
  20%, 80% { transform: translate3d(2px, 0, 0); }
  30%, 50%, 70% { transform: translate3d(-4px, 0, 0); }
  40%, 60% { transform: translate3d(4px, 0, 0); }
}

@keyframes scaleUp {
  0% { transform: scale(0.8); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes fade-up {
  0% { opacity: 0; transform: translate3d(0, 14px, 0); }
  100% { opacity: 1; transform: translate3d(0, 0, 0); }
}

@keyframes fade-in {
  0% { opacity: 0; }
  100% { opacity: 1; }
}

@keyframes marquee {
  0% { transform: translate3d(0, 0, 0); }
  100% { transform: translate3d(-50%, 0, 0); }
}

.animate-rotation {
  animation: rotation 1s linear infinite;
}

.animate-blinker {
  animation: blinker 1.06s step-end infinite;
}

.animate-shake {
  animation: shake 0.82s var(--ease-shake) both;
}

.animate-scale-up {
  animation: scaleUp var(--duration-base) var(--ease-out) both;
}

.fade-up {
  animation: fade-up var(--duration-slow) var(--ease-out) both;
}

.fade-in {
  animation: fade-in var(--duration-slow) var(--ease-out) both;
}

.fade-up-delay-1 { animation-delay: 80ms; }
.fade-up-delay-2 { animation-delay: 160ms; }
.fade-up-delay-3 { animation-delay: 240ms; }

.reveal {
  opacity: 0;
  transform: translate3d(0, 14px, 0);
  transition: opacity var(--duration-reveal) var(--ease-out),
              transform var(--duration-reveal) var(--ease-out);
}

.reveal.is-visible {
  opacity: 1;
  transform: translate3d(0, 0, 0);
}

.spinner {
  display: inline-block;
  width: 1.25rem;
  height: 1.25rem;
  border: 2px solid var(--color-gray-300);
  border-top-color: var(--color-primary);
  border-radius: var(--radius-full);
  animation: rotation 0.75s linear infinite;
}

.spinner--on-dark {
  border-color: rgba(255, 255, 255, 0.3);
  border-top-color: var(--color-accent);
}

.marquee {
  overflow: hidden;
  width: 100%;
}

.marquee-track {
  display: inline-flex;
  align-items: center;
  gap: var(--space-8);
  white-space: nowrap;
  animation: marquee 30s linear infinite;
}

.marquee:hover .marquee-track {
  animation-play-state: paused;
}

/* --------------------------------------------------------------------------
   9. Site footer
   -------------------------------------------------------------------------- */
.site-footer {
  background: var(--color-footer-bg);
  color: var(--color-footer-text);
  padding-block: var(--space-12) var(--space-8);
  margin-top: var(--space-12);
}

.footer-grid {
  display: grid;
  gap: var(--space-8);
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-10);
  }
}

.footer-brand {
  margin: 0 0 var(--space-2);
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: var(--weight-bold);
  color: var(--color-footer-heading);
}

.footer-tagline {
  margin: 0;
  max-width: 28rem;
  color: var(--color-footer-text);
  font-size: var(--text-sm);
}

.footer-heading {
  margin: 0 0 var(--space-3);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  color: var(--color-footer-heading);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-link {
  color: var(--color-footer-link);
  text-decoration: none;
  font-size: var(--text-sm);
  transition: color var(--duration-fast) var(--ease-out);
}

.footer-link:hover,
.footer-link:focus-visible {
  color: var(--color-footer-link-hover);
  text-decoration: underline;
}

.footer-code {
  margin: 0;
  background: rgba(0, 0, 0, 0.25);
  color: var(--color-overlay-90);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  font-size: var(--text-xs);
}

.footer-code code {
  background: transparent;
  color: inherit;
  padding: 0;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-top: var(--space-10);
  padding-top: var(--space-5);
  border-top: var(--border-width) solid var(--color-footer-border);
}

.footer-legal,
.footer-meta {
  margin: 0;
  font-size: var(--text-xs);
  color: var(--color-footer-text);
}

.footer-meta {
  font-family: var(--font-mono);
  letter-spacing: var(--tracking-wide);
}

/* --------------------------------------------------------------------------
   10. Reduced motion
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}