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

html {
  scroll-behavior: smooth;
  scroll-snap-type: y mandatory;
  -webkit-text-size-adjust: 100%;
  scrollbar-width: thin;
  scrollbar-color: var(--color-gold-dim) var(--color-noir);
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--color-champagne);
  background-color: var(--color-noir);
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

ul,
ol {
  list-style: none;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: calc(var(--rail-width) + var(--space-md));
  z-index: 9999;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-accent);
  color: var(--color-champagne);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.skip-link:focus {
  top: var(--space-md);
}

.container {
  width: min(100% - 2.5rem, var(--container-max));
  margin-inline: auto;
}

.chapter {
  scroll-snap-align: start;
  scroll-snap-stop: always;
  min-height: 100vh;
  min-height: 100dvh;
  position: relative;
}

main {
  margin-left: var(--rail-width);
}

.chapter--dark {
  background-color: var(--color-noir);
  color: var(--color-champagne);
}

.chapter--dark .section__eyebrow {
  color: var(--color-gold);
}

.chapter--dark .section__title {
  color: var(--color-champagne);
}

.chapter--dark .section__lead {
  color: var(--color-champagne-muted);
}

.chapter--light {
  background-color: var(--color-ivory);
  color: var(--color-ink);
}

.chapter--light .section__eyebrow {
  color: var(--color-accent);
}

.chapter--light .section__title {
  color: var(--color-ink);
}

.chapter--light .section__lead {
  color: var(--color-ink-soft);
}

.chapter__inner {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 100vh;
  min-height: 100dvh;
  padding-block: var(--space-3xl);
}

.section__eyebrow {
  display: inline-block;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  margin-bottom: var(--space-md);
}

.section__title {
  font-family: var(--font-display);
  font-size: clamp(var(--text-3xl), 4vw, var(--text-4xl));
  font-weight: 500;
  line-height: 1.12;
  margin-bottom: var(--space-md);
}

.section__lead {
  font-size: var(--text-lg);
  max-width: 52ch;
  margin-bottom: var(--space-2xl);
}

.fade-in {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-in.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.hidden {
  display: none !important;
}

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

@media (max-width: 768px) {
  main {
    margin-left: 0;
    padding-bottom: 72px;
  }

  .skip-link {
    left: var(--space-md);
  }

  .chapter__inner {
    padding-block: var(--space-2xl);
    min-height: auto;
  }

  .chapter {
    min-height: auto;
    scroll-snap-align: none;
    scroll-snap-stop: normal;
  }

  html {
    scroll-snap-type: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
    scroll-snap-type: none;
  }

  .fade-in {
    opacity: 1;
    transform: none;
    transition: none;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}