/* ==========================================================================
   Base element styling — typography defaults, links, focus, selection.
   ========================================================================== */

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: var(--text-base);
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  text-wrap: balance;
}

h1 {
  font-size: var(--text-4xl);
}

h2 {
  font-size: var(--text-2xl);
}

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

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

p {
  max-width: 70ch;
}

p + p {
  margin-block-start: var(--space-sm);
}

.font-display {
  font-family: var(--font-display);
}

strong,
b {
  font-weight: var(--weight-semibold);
}

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

a {
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:not([class]) {
  color: var(--color-accent-strong);
}

a:not([class]):hover {
  color: var(--color-teal-700);
}

/* Visible focus everywhere — never remove without an equivalent replacement */
:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

::selection {
  background-color: var(--color-teal-500);
  color: var(--color-paper-000);
}

hr {
  border: none;
  border-block-start: var(--border-hairline);
}

/* Skip link — visible only on keyboard focus */
.skip-link {
  position: absolute;
  inset-inline-start: var(--space-sm);
  inset-block-start: -100%;
  z-index: var(--z-skip-link);
  padding: var(--space-2xs) var(--space-sm);
  background-color: var(--color-ink-900);
  color: var(--color-text-inverse);
  border-radius: var(--radius-sm);
  font-family: var(--font-display);
  font-weight: var(--weight-medium);
  transition: top var(--duration-fast) var(--ease-standard);
}

.skip-link:focus {
  inset-block-start: var(--space-sm);
}

/* Inverse (dark-surface) sections */
.on-dark {
  background-color: var(--color-bg-inverse);
  color: var(--color-text-inverse);
}

.on-dark a:not([class]) {
  color: var(--color-accent-on-dark);
}

.on-dark ::selection {
  background-color: var(--color-teal-400);
  color: var(--color-ink-900);
}

/* Scroll-reveal enhancement (progressive — see js/animations.js) */
[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition:
    opacity var(--duration-reveal) var(--ease-out),
    transform var(--duration-reveal) var(--ease-out);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
}