* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--color-canvas);
  color: var(--color-text-primary);
  font-family: var(--font-body);
  font-weight: var(--font-weight-body-floor);
  font-size: 18px;
  line-height: 1.6;
}

h1, h2, h3 { font-family: var(--font-display); font-weight: 300; color: var(--color-text-primary); }

/* Links: bay blue everywhere, underline kept as a non-color affordance */
a {
  color: var(--color-text-primary);
  text-decoration: underline;
  text-decoration-color: var(--color-line-art);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
}
a:visited { color: var(--color-text-primary); }
a:hover, a:focus {
  text-decoration-color: var(--color-text-primary);
  text-decoration-thickness: 2px;
}

/* Layout container: centered content column with breathing room */
main,
header nav,
footer > *,
body > section,
body > .wave-divider {
  max-width: 72rem;
  margin-inline: auto;
  padding-inline: var(--space-2);
}
@media (min-width: 641px) {
  main,
  header nav,
  footer > *,
  body > section,
  body > .wave-divider {
    padding-inline: var(--space-3);
  }
}

/* Readable measure for prose */
main p, .chapter-text p, .how-to-use p, .media-card p, footer p {
  max-width: 65ch;
}

/* Pale-blue surfaces and hairlines */
header {
  background: var(--color-canvas-warm);
  border-bottom: 1px solid var(--color-surface-foam);
}
header nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  padding-block: var(--space-1);
}
header nav a {
  display: inline-block;
  padding: var(--space-1);
}
footer {
  background: var(--color-canvas-warm);
  border-top: 1px solid var(--color-surface-foam);
  padding-block: var(--space-2);
  margin-block-start: var(--space-4);
}
.how-to-use {
  background: var(--color-surface-pale);
  border: 1px solid var(--color-surface-foam);
  border-radius: 8px;
  padding: var(--space-3);
  margin-block: var(--space-3);
}

/* Wave divider: spans the content column between major sections */
.wave-divider {
  display: block;
  width: 100%;
  height: auto;
  opacity: 0.7;
  margin-block: var(--space-3);
}

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

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--color-text-primary);
  color: var(--color-canvas);
  padding: var(--space-1) var(--space-2);
  z-index: 100;
}
.skip-link:focus {
  left: var(--space-1);
  top: var(--space-1);
}

:focus-visible {
  outline: 3px solid var(--color-text-primary);
  outline-offset: 2px;
}

.reduced-motion * {
  animation: none !important;
  transition: none !important;
}