/* Page frame: hero, sidebar + article column, footer. Mobile-first, Flexbox only. */

.hero {
  position: relative;
  overflow: hidden;
  padding-block: 4.5rem 3.5rem;
  padding-inline: var(--gutter);
  text-align: center;
  border-block-end: 1px solid var(--line);

  &::before {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    background: radial-gradient(
      ellipse 60% 45% at 50% 0%,
      color-mix(in srgb, var(--accent) 10%, transparent),
      transparent 70%
    );
  }

  .eyebrow {
    font-size: 0.72rem;
    color: var(--ghost);
    margin-block: 0 1rem;
  }

  .title {
    position: relative;
    font-weight: 800;
    font-size: clamp(2.2rem, 6vw, 3.6rem);
    text-wrap: balance;

    .ghost-word {
      color: var(--accent);
      font-family: var(--font-body);
      font-style: italic;
      font-weight: 400;
    }
  }

  .subtitle {
    margin-block-start: 1rem;
    margin-inline: auto;
    max-inline-size: 40ch;
    color: var(--ink-soft);
    font-size: 1.05rem;
  }

  .tagline {
    margin-block-start: 1.75rem;
    font-family: var(--font-ui);
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ghost);
  }

  .hero-link {
    text-decoration: none;
    border-block-end: 1px solid
      color-mix(in srgb, currentColor 40%, transparent);
    padding-block-end: 0.2rem;
    transition: color 0.15s ease, border-color 0.15s ease;

    &:hover {
      color: var(--accent);
      border-block-end-color: currentColor;
    }
  }
}

.layout {
  display: flex;
  flex-direction: column;
  gap: var(--gutter);
  max-inline-size: var(--measure);
  margin-inline: auto;
  padding-block: 3rem 6rem;
  padding-inline: var(--gutter);

  @media (min-width: 54rem) {
    flex-direction: row;
    gap: 3rem;
  }
}

/* Horizontal scroller on small screens, sticky rail from 54rem up. */
.toc {
  font-family: var(--font-ui);
  overflow-x: auto;
  padding-block-end: 0.5rem;

  ol {
    display: flex;
    gap: 0.25rem;
    list-style: none;
    margin: 0;
    padding: 0;
    white-space: nowrap;
    border-block-end: 1px solid var(--line);
  }

  a {
    display: block;
    padding-block: 0.4rem;
    padding-inline: 0.7rem;
    text-decoration: none;
    font-size: var(--text-small);
    color: var(--ink-soft);
    border-block-end: 2px solid transparent;
    transition:
      color 0.15s ease,
      border-color 0.15s ease;

    &:hover {
      color: var(--ink);
      border-block-end-color: var(--ghost);
    }
  }

  .roman {
    color: var(--accent);
    font-weight: 700;
    margin-inline-end: 0.4em;
  }

  @media (min-width: 54rem) {
    flex: 0 0 13.75rem;
    position: sticky;
    inset-block-start: 2rem;
    align-self: start;
    overflow: visible;
    padding-block-end: 0;

    ol {
      flex-direction: column;
      gap: 0;
      white-space: normal;
      border-block-end: none;
      border-inline-start: 1px solid var(--line);
    }

    a {
      padding-inline: 1rem 0;
      margin-inline-start: -1px;
      border-block-end: none;
      border-inline-start: 2px solid transparent;

      &:hover {
        border-inline-start-color: var(--ghost);
      }
    }
  }
}

/* Named container so article components size to this column, not the viewport. */
main {
  flex: 1 1 auto;
  min-inline-size: 0;
  container: content / inline-size;
}

.rule {
  padding-block: 2.75rem;
  border-block-end: 1px solid var(--line);
  scroll-margin-block-start: 2rem;

  &:first-of-type {
    padding-block-start: 0;
  }

  &:last-of-type {
    border-block-end: none;
  }

  p {
    color: var(--ink);

    &.soft {
      color: var(--ink-soft);
    }
  }
}

.rule-head {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  margin-block-end: 1.1rem;

  h2 {
    font-weight: 800;
    font-size: 1.5rem;
  }
}

.rule-num {
  font-family: var(--font-ui);
  font-weight: 800;
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  color: var(--accent);
}

footer {
  text-align: center;
  padding-block: 2.5rem 3.5rem;
  padding-inline: var(--gutter);
  font-family: var(--font-ui);
  font-size: 0.78rem;
  color: var(--ghost);
}