/* Base: reset, layout scaffolding, nav, typography. */

@layer reset, base, components;

@layer reset {
  *, *::before, *::after { box-sizing: border-box; }
  body, h1, h2, h3, h4, p, figure, blockquote, dl, dd { margin: 0; }
  img, svg, canvas { display: block; max-width: 100%; }
  input, button, select { font: inherit; }
}

@layer base {
  html {
    scroll-behavior: smooth;
    scroll-padding-top: 5rem;
  }

  body {
    background:
      radial-gradient(1200px 700px at 85% -10%, color-mix(in oklab, var(--ink-700) 55%, transparent), transparent 70%),
      radial-gradient(900px 600px at -10% 30%, color-mix(in oklab, #143a4a 45%, transparent), transparent 65%),
      var(--bg);
    color: var(--text-300);
    font-family: var(--font-body);
    font-size: var(--fs-body);
    line-height: 1.65;
    min-height: 100dvh;
  }

  /* Faint engineering grid over the whole page */
  body::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    background:
      linear-gradient(to right, rgb(79 216 235 / .025) 1px, transparent 1px) 0 0 / 56px 56px,
      linear-gradient(to bottom, rgb(79 216 235 / .025) 1px, transparent 1px) 0 0 / 56px 56px;
    z-index: 0;
  }

  h1, h2, h3 {
    font-family: var(--font-display);
    font-weight: 550;
    color: var(--text-100);
    line-height: 1.12;
    text-wrap: balance;
  }
  h1 { font-size: var(--fs-h1); }
  h2 { font-size: var(--fs-h2); }
  h3 { font-size: var(--fs-h3); }

  p { max-width: 62ch; text-wrap: pretty; }

  a { color: var(--accent); text-underline-offset: 3px; }
  a:hover { color: color-mix(in oklab, var(--accent) 70%, white); }

  code, .mono { font-family: var(--font-mono); font-size: 0.92em; }

  :focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
    border-radius: 2px;
  }

  ::selection { background: color-mix(in oklab, var(--accent) 35%, transparent); }

  main {
    position: relative;
    z-index: 1;
    max-width: var(--content-w);
    margin-inline: auto;
    padding: var(--sp-5) var(--sp-3) var(--sp-6);
  }

  section { margin-block: var(--sp-6); scroll-margin-top: 5.5rem; }

  /* ------ shared page furniture ------ */

  .sr-only {
    position: absolute;
    inline-size: 1px;
    block-size: 1px;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
  }

  .skip-link {
    position: absolute;
    top: 0.5rem;
    left: 0.5rem;
    z-index: 100;
    background: var(--accent);
    color: var(--bg-deep);
    font-family: var(--font-mono);
    font-size: var(--fs-small);
    font-weight: 600;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 999px;
    transform: translateY(-300%);
  }
  .skip-link:focus { transform: none; }

  .site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: color-mix(in oklab, var(--bg-deep) 82%, transparent);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--line);
  }
  .site-header .bar {
    max-width: var(--content-w);
    margin-inline: auto;
    padding: 0.7rem var(--sp-3);
    display: flex;
    align-items: center;
    gap: var(--sp-3);
    flex-wrap: wrap;
  }
  .site-title {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    letter-spacing: 0.08em;
    color: var(--text-100);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    white-space: nowrap;
  }
  .site-title .pip {
    inline-size: 9px;
    block-size: 9px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: var(--glow-accent);
  }
  .site-nav { margin-inline-start: auto; display: flex; gap: 0.25rem; flex-wrap: wrap; }
  .site-nav a {
    font-family: var(--font-mono);
    font-size: var(--fs-tiny);
    letter-spacing: 0.05em;
    text-decoration: none;
    color: var(--text-500);
    padding: 0.45rem 0.7rem;
    border-radius: 999px;
    border: 1px solid transparent;
  }
  .site-nav a:hover { color: var(--text-100); border-color: var(--line); }
  .site-nav a:focus-visible { border-radius: 999px; }
  .site-nav a[aria-current="page"] {
    color: var(--bg-deep);
    background: var(--accent);
    font-weight: 600;
  }

  /* Mobile: nav.js collapses the pills behind a MENU button. Without JS
     (no body.has-navjs) the nav simply wraps, as before. */
  .nav-toggle { display: none; }
  @media (max-width: 44rem) {
    body.has-navjs .nav-toggle {
      display: inline-block;
      margin-inline-start: auto;
      font-family: var(--font-mono);
      font-size: var(--fs-tiny);
      letter-spacing: 0.05em;
      color: var(--text-300);
      background: transparent;
      border: 1px solid var(--line);
      border-radius: 999px;
      padding: 0.45rem 0.7rem;
      cursor: pointer;
    }
    body.has-navjs .site-nav { display: none; }
    body.has-navjs .site-nav.open { display: flex; flex-basis: 100%; }
  }

  .site-footer {
    position: relative;
    z-index: 1;
    border-top: 1px solid var(--line);
    margin-top: var(--sp-6);
    padding: var(--sp-4) var(--sp-3);
    font-size: var(--fs-small);
    color: var(--text-500);
  }
  .site-footer .bar {
    max-width: var(--content-w);
    margin-inline: auto;
    display: flex;
    gap: var(--sp-3);
    flex-wrap: wrap;
    justify-content: space-between;
  }

  /* Section kicker: "01 / THE SOURCE" style */
  .kicker {
    font-family: var(--font-mono);
    font-size: var(--fs-tiny);
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--accent);
    display: block;
    margin-bottom: var(--sp-2);
  }

  .lede {
    font-size: 1.18rem;
    color: var(--text-300);
    max-width: 56ch;
  }

  .page-intro { max-width: 46rem; margin-block: var(--sp-5); }
  .page-intro h1 { margin-bottom: var(--sp-3); }
}

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