/* =============================================================
   AFBB Prototype — Base Styles
   Uses semantic design tokens from tokens.css
============================================================= */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--primitive-font-family-sans);
  font-size: var(--typography-body-font-size);
  line-height: var(--typography-body-line-height);
  color: var(--color-text-default);
  background-color: var(--color-surface-background);
}

/* ── Container ─────────────────────────────────────────────── */
.container {
  max-width: var(--primitive-layout-container-max-width);
  margin-inline: auto;
  padding-inline: var(--spacing-component-lg);
}

/* ── Navigation ────────────────────────────────────────────── */
.nav {
  background-color: var(--color-surface-card);
  border-bottom: var(--border-width-default) solid var(--color-border-default);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--size-button-lg);
}

.nav__logo {
  font-size: var(--typography-h4-font-size);
  font-weight: 700;
  color: var(--color-brand-default);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav__links {
  display: flex;
  gap: var(--spacing-component-md);
  list-style: none;
}

.nav__link {
  font-size: var(--typography-ui-font-size);
  line-height: var(--typography-ui-line-height);
  color: var(--color-text-muted);
  text-decoration: none;
  padding: var(--spacing-component-xs) var(--spacing-component-sm);
  border-radius: var(--radius-component-sm);
  transition: color var(--motion-duration-fast) var(--motion-easing-standard),
              background-color var(--motion-duration-fast) var(--motion-easing-standard);
}

.nav__link:hover {
  color: var(--color-text-default);
  background-color: var(--color-surface-secondary);
}

.nav__link--active {
  color: var(--color-brand-default);
  font-weight: 500;
}

/* ── Page ───────────────────────────────────────────────────── */
.page {
  padding-block: var(--spacing-section-md);
}

/* ── Typography ────────────────────────────────────────────── */
h1 {
  font-size: var(--typography-h1-font-size);
  line-height: var(--typography-h1-line-height);
  color: var(--color-text-strong);
  font-weight: 700;
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--typography-h2-font-size);
  line-height: var(--typography-h2-line-height);
  color: var(--color-text-strong);
  font-weight: 700;
}

h3 {
  font-size: var(--typography-h3-font-size);
  line-height: var(--typography-h3-line-height);
  color: var(--color-text-strong);
  font-weight: 600;
}

h4 {
  font-size: var(--typography-h4-font-size);
  line-height: var(--typography-h4-line-height);
  color: var(--color-text-strong);
  font-weight: 600;
}

p {
  color: var(--color-text-default);
  font-size: var(--typography-body-font-size);
  line-height: var(--typography-body-line-height);
}

a {
  color: var(--color-text-link);
  text-decoration: none;
  transition: color var(--motion-duration-fast) var(--motion-easing-standard);
}

a:hover {
  color: var(--color-text-link-hover);
}

/* ── Utility: Visually Hidden ─────────────────────────────── */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}