.arctn-page .tutorial-layout { width: min(calc(100% - 2 * var(--page-pad)), 1320px); grid-template-columns: 240px minmax(0, 1fr); gap: clamp(28px, 4vw, 64px); }
.arctn-page .tutorial-article { max-width: none; container: article / inline-size; }
.arctn-directory > summary { font-size: 16px; font-weight: 500; cursor: pointer; padding: 0 0 16px; }
.arctn-filter { margin-bottom: 16px; }
.arctn-filter label { display: block; color: var(--theme-muted); font-size: 12px; margin-bottom: 8px; }
.arctn-filter input { width: 100%; min-width: 0; min-height: 42px; padding: 8px 12px; border: 1px solid var(--theme-line); border-radius: 4px; background: var(--theme-surface); color: var(--theme-ink); font: inherit; font-size: 13px; }
.arctn-group { margin-bottom: 10px; }
.arctn-group summary { padding: 10px 0; color: var(--theme-muted); font-size: 13px; cursor: pointer; }
.arctn-group a { display: block; padding: 8px 12px; min-height: 40px; border-left: 2px solid transparent; font-size: 13px; line-height: 1.65; overflow-wrap: anywhere; }
.arctn-group a[aria-current="page"] { color: var(--theme-accent); border-left-color: var(--theme-accent); background: var(--theme-surface); }
.arctn-empty { font-size: 13px; color: var(--theme-muted); }
.arctn-directory [hidden] { display: none !important; }
.arctn-page .tutorial-toc { margin-block: 24px; padding: 12px 16px; border: 1px solid var(--theme-line); border-radius: 4px; }
.arctn-page .tutorial-toc nav { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 24px; }
.arctn-page .tutorial-article h3 { margin-top: 30px; font-size: 20px; font-weight: 500; line-height: 1.5; scroll-margin-top: calc(var(--header-height) + 16px); }
.arctn-page blockquote { margin: 24px 0; padding: 12px 18px; border-left: 2px solid var(--theme-accent); background: var(--theme-surface); }
.arctn-page blockquote p { margin: 8px 0; }
.arctn-page .arctn-warning { border-left-color: #e8bb6b; }
.arctn-pager { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--theme-line); }
.arctn-pager a { display: flex; flex-direction: column; padding: 12px; border: 1px solid var(--theme-line); border-radius: 4px; text-decoration: none; }
.arctn-pager span { color: var(--theme-muted); font-size: 12px; }
.arctn-next { grid-column: 2; text-align: right; }

/* Diagram palette: dark surfaces, readable labels, and distinct algorithm states. */
.arctn-figure {
  --docs-paper: #000; --docs-sidebar: #121416; --docs-surface: #101214; --docs-surface-muted: #191c20;
  --docs-ink: #f2f4f5; --docs-ink-soft: #c3cad1; --docs-ink-faint: #a0aab4;
  --docs-line: #343b43; --docs-line-strong: #64717e;
  --docs-accent: #c5ef63; --docs-accent-bright: #ddff91; --docs-accent-soft: #202b12;
  --docs-on-accent: #101508; --docs-accent-line: #92b64a;
  --docs-code-bg: #1c2025; --docs-code-ink: #e4e9ef;
  --docs-warning-bg: #302311; --docs-warning-line: #dba657; --docs-warning-ink: #f5ca86;
  --docs-figure-line: #91a1af; --docs-figure-label: #c3ced8;
  --docs-refinement: #efa477; --docs-refinement-soft: #302018; --docs-refinement-ink: #ffc49e;
  --docs-success: #92dfae; --docs-danger: #ff9c9c;
  margin: 24px 0; padding: 16px; background: var(--docs-paper); color: var(--docs-ink); color-scheme: dark;
  border-radius: 6px; min-width: 0; overflow-x: auto;
}
:root body #main .arctn-figure :is(section, header) { color: var(--docs-ink); background: transparent; }
:root body #main .arctn-figure :is(p, li, h2, h3, small, code) { color: inherit; font-size: inherit; }
:root body #main .arctn-figure :not(pre) > code { background: var(--docs-code-bg); padding: 2px 4px; }
.arctn-figure :is(p, dl, dd) { margin: 0; }
.arctn-figure .docs-technical-diagram { margin: 0; max-width: 100%; border: 0; }
.arctn-figure svg { max-width: 100%; }
.arctn-figure figcaption { color: var(--docs-ink-faint); }
@media (max-width: 980px) {
  .arctn-page .tutorial-layout { grid-template-columns: minmax(0, 1fr); }
  .arctn-directory { padding-bottom: 8px; border-bottom: 1px solid var(--theme-line); }
}
@media (max-width: 480px) {
  .arctn-page .tutorial-toc nav, .arctn-pager { grid-template-columns: 1fr; }
  .arctn-next { grid-column: auto; text-align: left; }
  .arctn-figure { padding: 10px; }
}