/* ============================================================
 * base.css — reset, root typography, shared primitives
 * Depends on tokens.css (loaded first in index.html)
 * ============================================================ */

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  overflow-x: clip;
  scroll-behavior: smooth;
  /* offset anchor jumps so the sticky header never hides section tops */
  scroll-padding-top: 5rem;
  color-scheme: light;
}

body {
  margin: 0;
  overflow-x: clip;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--step-0);
  font-weight: 400;
  line-height: 1.62;
  font-variant-numeric: tabular-nums;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* Headings — Hanken Grotesk (display) */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0;
  overflow-wrap: anywhere;
  min-width: 0;
  color: var(--text);
}

p { margin: 0; }

a {
  color: var(--text);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  text-decoration-color: var(--rule-strong);
  transition: text-decoration-color var(--dur-fast) var(--ease-precise),
              color var(--dur-fast) var(--ease-precise);
}
a:hover { text-decoration-color: var(--accent); color: var(--accent); }

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

button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }

ul, ol { margin: 0; padding: 0; list-style: none; }

strong { font-weight: 600; color: var(--text); }
em { font-style: italic; }

hr { border: 0; border-top: 1px solid var(--rule); margin: 0; }

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

/* Focus ring: visible, sharp, not neon */
:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 3px;
  border-radius: var(--radius-1);
}

/* Skip link */
.skip-link {
  position: fixed;
  top: var(--space-xs);
  left: var(--space-xs);
  z-index: var(--z-skip);
  padding: var(--space-xs) var(--space-sm);
  background: var(--accent);
  color: var(--accent-ink);
  text-decoration: none;
  font-size: var(--step--1);
  font-weight: 600;
  border-radius: var(--radius-1);
  transform: translateY(-150%);
  transition: transform var(--dur-fast) var(--ease-precise);
}
.skip-link:focus { transform: translateY(0); }

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

/* Section scaffold — ruled blocks with an index in the margin */
.section {
  padding-block: var(--space-3xl);
  border-top: 1px solid var(--rule);
}
.section--first { border-top: 0; padding-top: var(--space-2xl); }

.section__head {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-s);
  border-bottom: 1px solid var(--rule);
}
.section__index {
  font-family: var(--font-display);
  font-size: var(--step-3);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}
.section__sep {
  margin: 0 0.35em;
  color: var(--text-faint);
  font-weight: 400;
}

/* Rise entrance — one orchestrated reveal, staggered by --i */
.rise {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity var(--dur-slow) var(--ease-quiet),
              transform var(--dur-slow) var(--ease-quiet);
  transition-delay: calc(var(--i, 0) * 70ms);
}
.rise.is-in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .rise {
    opacity: 0;
    transform: none;
    transition: opacity 150ms linear;
    transition-delay: 0ms;
  }
  .rise.is-in { opacity: 1; }
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

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