/* tsuki: table of contents — sticky on wide, collapsible on narrow */

.toc {
  font-size: var(--tsuki-fs-sm);
  color: var(--tsuki-fg-muted);
}
.toc-heading {
  font-size: var(--tsuki-fs-sm);
  font-weight: 600;
  margin: 0 0 var(--tsuki-space-3);
  color: var(--tsuki-fg);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.toc nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.toc nav ul ul {
  padding-inline-start: var(--tsuki-space-3);
  margin-block-start: var(--tsuki-space-1);
}
.toc nav li { margin-block: var(--tsuki-space-1); }
.toc nav a {
  display: block;
  padding: 0.125rem 0;
  color: var(--tsuki-fg-muted);
  border-inline-start: 2px solid transparent;
  padding-inline-start: var(--tsuki-space-3);
  margin-inline-start: calc(-1 * var(--tsuki-space-3));
  transition: var(--tsuki-transition);
}
.toc nav a:hover { color: var(--tsuki-fg); text-decoration: none; }
.toc nav a[aria-current="true"] {
  color: var(--tsuki-accent);
  border-inline-start-color: var(--tsuki-accent);
  font-weight: 550;
}

/* wide layout: 2-col grid with sticky toc */
@media (min-width: 64rem) {
  body.post main {
    max-width: var(--tsuki-wide-width);
    display: grid;
    grid-template-columns: 1fr 14rem;
    gap: var(--tsuki-space-12);
    align-items: start;
  }
  body.post .post { min-width: 0; }
  body.post .toc {
    position: sticky;
    inset-block-start: var(--tsuki-space-6);
    max-block-size: calc(100vh - var(--tsuki-space-12));
    overflow-y: auto;
  }
}

/* narrow: framed block above content */
@media (max-width: 63.99rem) {
  .toc {
    margin-block-end: var(--tsuki-space-8);
    padding: var(--tsuki-space-4);
    border: 1px solid var(--tsuki-border);
    border-radius: var(--tsuki-radius);
  }
}