/* ==========================================================================
   Example Hub — Shared Design System
   The single source of truth every page links to. Defines tokens, base
   element styles, layout primitives, components, site chrome and motion.
   Mobile-first: base rules target small screens, min-width queries scale up.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Design tokens
   -------------------------------------------------------------------------- */
:root {
  color-scheme: light dark;

  /* Brand */
  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-active: #3730a3;
  --color-primary-soft: #eef2ff;
  --color-primary-contrast: #ffffff;

  --color-secondary: #0d9488;
  --color-secondary-hover: #0f766e;
  --color-secondary-soft: #ccfbf1;

  --color-accent: #f59e0b;
  --color-accent-soft: #fef3c7;

  --color-success: #6b8f71;
  --color-success-soft: #e6efe7;
  --color-danger: #dc2626;
  --color-danger-soft: #fee2e2;

  /* Neutral ramp */
  --neutral-50: #fafafa;
  --neutral-100: #f5f5f4;
  --neutral-200: #e4e4e7;
  --neutral-300: #d4d4d8;
  --neutral-400: #a1a1aa;
  --neutral-500: #71717a;
  --neutral-600: #52525b;
  --neutral-700: #3f3f46;
  --neutral-800: #27272a;
  --neutral-900: #18181b;

  /* Semantic surfaces */
  --color-bg: var(--neutral-100);
  --color-surface: #ffffff;
  --color-surface-sunken: var(--neutral-50);
  --color-border: var(--neutral-200);
  --color-border-strong: var(--neutral-300);
  --color-text: #1c1c1e;
  --color-text-muted: var(--neutral-600);
  --color-text-subtle: var(--neutral-500);
  --color-text-inverse: #f4f4f5;

  /* Typography */
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial,
    "Noto Sans", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", "Source Code Pro",
    Menlo, Consolas, monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  --leading-tight: 1.15;
  --leading-snug: 1.3;
  --leading-normal: 1.6;
  --leading-relaxed: 1.75;

  --weight-regular: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;

  /* 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;
  --space-24: 6rem;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Elevation */
  --shadow-xs: 0 1px 2px rgba(24, 24, 27, 0.06);
  --shadow-sm: 0 1px 3px rgba(24, 24, 27, 0.08),
    0 1px 2px rgba(24, 24, 27, 0.04);
  --shadow-md: 0 4px 12px rgba(24, 24, 27, 0.08),
    0 2px 4px rgba(24, 24, 27, 0.04);
  --shadow-lg: 0 12px 32px rgba(24, 24, 27, 0.12),
    0 4px 8px rgba(24, 24, 27, 0.05);

  /* Motion */
  --duration-fast: 150ms;
  --duration-base: 300ms;
  --duration-slow: 600ms;
  --ease-standard: cubic-bezier(0.2, 0, 0, 1);
  --ease-emphasized: cubic-bezier(0.22, 0.61, 0.36, 1);

  /* Layout */
  --container-max: 64rem;
  --container-narrow: 44rem;
  --header-height: 4rem;

  --focus-ring: 0 0 0 3px rgba(79, 70, 229, 0.35);
}

/* Dark theme — follows the OS by default, overridable via [data-theme]. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-primary: #818cf8;
    --color-primary-hover: #a5b4fc;
    --color-primary-active: #c7d2fe;
    --color-primary-soft: #1e1b4b;
    --color-primary-contrast: #1e1b4b;

    --color-secondary: #2dd4bf;
    --color-secondary-hover: #5eead4;
    --color-secondary-soft: #042f2e;

    --color-accent: #fbbf24;
    --color-accent-soft: #422006;

    --color-success: #86b18c;
    --color-success-soft: #14261a;
    --color-danger: #f87171;
    --color-danger-soft: #3f1414;

    --color-bg: #18181b;
    --color-surface: #232326;
    --color-surface-sunken: #1c1c1f;
    --color-border: #2e2e34;
    --color-border-strong: #3f3f46;
    --color-text: #f4f4f5;
    --color-text-muted: #a1a1aa;
    --color-text-subtle: #8b8b93;
    --color-text-inverse: #18181b;

    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.45), 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.45), 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.55), 0 4px 8px rgba(0, 0, 0, 0.4);

    --focus-ring: 0 0 0 3px rgba(129, 140, 248, 0.45);
  }
}

:root[data-theme="dark"] {
  --color-primary: #818cf8;
  --color-primary-hover: #a5b4fc;
  --color-primary-active: #c7d2fe;
  --color-primary-soft: #1e1b4b;
  --color-primary-contrast: #1e1b4b;

  --color-secondary: #2dd4bf;
  --color-secondary-hover: #5eead4;
  --color-secondary-soft: #042f2e;

  --color-accent: #fbbf24;
  --color-accent-soft: #422006;

  --color-success: #86b18c;
  --color-success-soft: #14261a;
  --color-danger: #f87171;
  --color-danger-soft: #3f1414;

  --color-bg: #18181b;
  --color-surface: #232326;
  --color-surface-sunken: #1c1c1f;
  --color-border: #2e2e34;
  --color-border-strong: #3f3f46;
  --color-text: #f4f4f5;
  --color-text-muted: #a1a1aa;
  --color-text-subtle: #8b8b93;
  --color-text-inverse: #18181b;

  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.45), 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.45), 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.55), 0 4px 8px rgba(0, 0, 0, 0.4);

  --focus-ring: 0 0 0 3px rgba(129, 140, 248, 0.45);
}

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

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

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

h1,
h2,
h3,
h4 {
  margin: 0 0 var(--space-4);
  color: var(--color-text);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(2rem, 1.4rem + 3vw, var(--text-5xl));
}

h2 {
  font-size: clamp(1.5rem, 1.2rem + 1.6vw, var(--text-3xl));
}

h3 {
  font-size: var(--text-2xl);
}

h4 {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  text-underline-offset: 2px;
}

a:hover {
  text-decoration: underline;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: none;
  border-radius: var(--radius-sm);
  box-shadow: var(--focus-ring);
}

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

ul,
ol {
  margin: 0 0 var(--space-4);
  padding-left: var(--space-6);
}

code,
kbd,
pre,
samp {
  font-family: var(--font-mono);
  font-size: 0.925em;
}

code {
  padding: 0.15em 0.35em;
  border-radius: var(--radius-sm);
  background: var(--color-surface-sunken);
  border: 1px solid var(--color-border);
}

pre {
  margin: 0 0 var(--space-4);
  padding: var(--space-4);
  overflow-x: auto;
  border-radius: var(--radius-md);
  background: var(--neutral-900);
  color: var(--neutral-100);
  line-height: var(--leading-snug);
}

pre code {
  padding: 0;
  border: 0;
  background: none;
  color: inherit;
}

hr {
  border: 0;
  border-top: 1px solid var(--color-border);
  margin-block: var(--space-8);
}

::selection {
  background: var(--color-primary);
  color: var(--color-primary-contrast);
}

/* --------------------------------------------------------------------------
   3. Typography utilities
   -------------------------------------------------------------------------- */
.eyebrow {
  display: inline-block;
  margin: 0 0 var(--space-3);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary);
}

.lead {
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  color: var(--color-text-muted);
}

.text-small {
  font-size: var(--text-sm);
}

.text-muted {
  color: var(--color-text-muted);
}

.text-subtle {
  color: var(--color-text-subtle);
}

.text-accent {
  color: var(--color-primary);
}

.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;
}

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -3rem;
  z-index: 100;
  padding: var(--space-2) var(--space-4);
  background: var(--color-primary);
  color: var(--color-primary-contrast);
  border-radius: var(--radius-md);
  transition: top var(--duration-fast) var(--ease-standard);
}

.skip-link:focus {
  top: var(--space-2);
}

/* --------------------------------------------------------------------------
   4. Layout primitives
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

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

@media (min-width: 48rem) {
  .container {
    padding-inline: var(--space-8);
  }
}

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

@media (min-width: 48rem) {
  .section {
    padding-block: var(--space-16);
  }
}

.stack > * + * {
  margin-top: var(--space-4);
}

.flex {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  align-items: center;
}

.flex-between {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
}

.flex-center {
  display: flex;
  gap: var(--space-4);
  align-items: center;
  justify-content: center;
}

.grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 40rem) {
  .grid-2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 48rem) {
  .grid-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 64rem) {
  .grid-4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* --------------------------------------------------------------------------
   5. Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  font: inherit;
  font-weight: var(--weight-semibold);
  line-height: 1.1;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  transition: background-color var(--duration-fast) var(--ease-standard),
    border-color var(--duration-fast) var(--ease-standard),
    color var(--duration-fast) var(--ease-standard),
    box-shadow var(--duration-fast) var(--ease-standard),
    transform var(--duration-fast) var(--ease-standard);
}

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

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

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

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

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

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

.btn-secondary:hover {
  background-color: var(--color-surface-sunken);
  color: var(--color-primary);
  border-color: var(--color-primary);
}

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

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

.btn-sm {
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
}

.btn-lg {
  padding: var(--space-4) var(--space-6);
  font-size: var(--text-lg);
}

.btn-block {
  width: 100%;
}

/* --------------------------------------------------------------------------
   6. Cards & badges
   -------------------------------------------------------------------------- */
.card {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-6);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--duration-base) var(--ease-standard),
    transform var(--duration-base) var(--ease-standard),
    border-color var(--duration-base) var(--ease-standard);
}

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

.card__title {
  margin: 0;
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
}

.card__text {
  margin: 0;
  color: var(--color-text-muted);
}

.card__footer {
  margin-top: auto;
  padding-top: var(--space-3);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.02em;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
}

.badge-accent {
  background-color: var(--color-accent-soft);
  color: #92400e;
}

:root[data-theme="dark"] .badge-accent {
  color: var(--color-accent);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .badge-accent {
    color: var(--color-accent);
  }
}

/* --------------------------------------------------------------------------
   7. Site chrome — header / nav / footer
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(8px);
}

.site-header__inner {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: var(--header-height);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: var(--weight-bold);
  color: var(--color-text);
  letter-spacing: -0.01em;
}

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

.brand__mark {
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: var(--radius-md);
  background-color: var(--color-primary);
  color: var(--color-primary-contrast);
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
}

.brand__name {
  font-size: var(--text-lg);
}

/* Primary navigation — always visible at every width, no JS required. */
.site-nav {
  display: block;
}

.site-nav__list {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  width: auto;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__link {
  display: block;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
  transition: color var(--duration-fast) var(--ease-standard),
    background-color var(--duration-fast) var(--ease-standard);
}

.site-nav__link:hover {
  color: var(--color-text);
  background-color: var(--color-surface-sunken);
  text-decoration: none;
}

.site-nav__link[aria-current="page"] {
  color: var(--color-primary);
}

.site-footer {
  margin-top: var(--space-16);
  padding-block: var(--space-12) var(--space-6);
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
}

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

.footer-col {
  min-width: 0;
}

@media (min-width: 48rem) {
  .footer-grid {
    grid-template-columns: 1.6fr 1fr 1fr;
  }
}

.footer-heading {
  margin: 0 0 var(--space-3);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-subtle);
}

.footer-tagline {
  max-width: 34ch;
  margin: var(--space-4) 0 0;
}

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

.footer-links a {
  color: var(--color-text-muted);
}

.footer-links a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-10);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
  font-size: var(--text-sm);
  color: var(--color-text-subtle);
}

.footer-bottom p {
  margin: 0;
}

/* --------------------------------------------------------------------------
   8. Motion — reusable reveal / fade / marquee utilities
   -------------------------------------------------------------------------- */
.reveal {
  opacity: 0;
  transform: translateY(1rem);
  transition: opacity var(--duration-slow) var(--ease-emphasized),
    transform var(--duration-slow) var(--ease-emphasized);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

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

@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(1.25rem);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.marquee {
  position: relative;
  overflow: hidden;
}

.marquee__track {
  display: flex;
  gap: var(--space-8);
  width: max-content;
  animation: marquee 30s linear infinite;
}

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

@keyframes marquee {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(-50%);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

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