:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #21262d;
  --border: #30363d;
  --text: #c9d1d9;
  --muted: #8b949e;
  --bright: #f0f6fc;
  --green: #3fb950;
  --blue: #58a6ff;
  --orange: #f0883e;
  --red: #ff7b72;
  --mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;
  --sans: 'Noto Sans JP', 'Hiragino Sans', 'Yu Gothic', sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.9 var(--sans);
  transition: background .2s, color .2s;
}
body.mode-light {
  --bg: #fff;
  --surface: #f6f8fa;
  --surface-2: #eaeef2;
  --border: #d0d7de;
  --text: #1f2328;
  --muted: #656d76;
  --bright: #0a0c10;
  --green: #1a7f37;
  --blue: #0969da;
  --orange: #bc4c00;
  --red: #cf222e;
}
a { color: var(--blue); }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible, button:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; }
.reading-progress {
  position: fixed; inset: 0 auto auto 0; z-index: 100; width: 100%; height: 3px;
  background: linear-gradient(90deg, var(--green), var(--blue)); transform: scaleX(0); transform-origin: left;
}
.titlebar {
  position: sticky; top: 0; z-index: 90; min-height: 44px; padding: 7px 18px;
  display: flex; align-items: center; gap: 10px; border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface) 94%, transparent); backdrop-filter: blur(12px);
}
.titlebar-dots { display: flex; gap: 6px; }
.titlebar-dots span { width: 11px; height: 11px; border-radius: 50%; }
.dot-red { background: #ff5f56; } .dot-yellow { background: #ffbd2e; } .dot-green { background: #27c93f; }
.titlebar-path { min-width: 0; overflow: hidden; color: var(--muted); font: 12px/1.4 var(--mono); text-overflow: ellipsis; white-space: nowrap; }
.mode-toggle { margin-left: auto; min-width: 70px; min-height: 34px; border: 1px solid var(--border); border-radius: 999px; background: var(--surface-2); color: var(--text); cursor: pointer; }
.shell { width: min(960px, calc(100% - 32px)); margin: 0 auto; padding: 48px 0 72px; }
.breadcrumb { margin-bottom: 24px; color: var(--muted); font: 13px/1.6 var(--mono); }
.breadcrumb a { text-decoration: none; }
.eyebrow { color: var(--green); font: 600 13px/1.4 var(--mono); letter-spacing: .04em; }
.article-header { margin-bottom: 42px; }
h1 { margin: 12px 0 18px; color: var(--bright); font-size: clamp(30px, 5vw, 52px); line-height: 1.35; letter-spacing: -.03em; }
.lead { max-width: 780px; color: var(--muted); font-size: 18px; }
.meta { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 22px; color: var(--muted); font: 13px/1.5 var(--mono); }
.article-body { max-width: 800px; }
.article-body h2 { margin: 64px 0 20px; padding-top: 16px; border-top: 1px solid var(--border); color: var(--bright); font-size: clamp(24px, 3vw, 32px); line-height: 1.5; }
.article-body h3 { margin: 38px 0 12px; color: var(--bright); font-size: 21px; line-height: 1.55; }
.article-body h2, .article-body h3 { scroll-margin-top: 64px; }
.article-body p { margin: 0 0 22px; }
.article-body strong { color: var(--bright); }
.article-body code { padding: .15em .38em; border: 1px solid var(--border); border-radius: 5px; background: var(--surface); color: var(--bright); font: .88em/1.5 var(--mono); }
.article-body pre { margin: 24px 0; padding: 20px; overflow-x: auto; border: 1px solid var(--border); border-radius: 10px; background: #090c10; }
body.mode-light .article-body pre { background: #f6f8fa; }
.article-body pre code { padding: 0; border: 0; background: none; }
.article-body blockquote { margin: 28px 0; padding: 16px 20px; border-left: 4px solid var(--green); background: var(--surface); color: var(--bright); }
.article-body blockquote p:last-child { margin-bottom: 0; }
.article-body ul, .article-body ol { margin: 0 0 24px; padding-left: 1.5em; }
.article-body li { margin: 7px 0; }
.article-body table { width: 100%; margin: 26px 0; border-collapse: collapse; font-size: 14px; }
.article-body th, .article-body td { padding: 11px 13px; border: 1px solid var(--border); text-align: left; vertical-align: top; }
.article-body th { background: var(--surface-2); color: var(--bright); }
.table-scroll { width: 100%; margin: 26px 0; overflow-x: auto; }
.table-scroll table { min-width: 640px; margin: 0; }
.diagram-scroll { width: calc(100vw - 32px); max-width: 1100px; margin: 32px 0 12px; overflow-x: auto; border: 1px solid var(--border); border-radius: 12px; background: #fff; }
.diagram-scroll img { display: block; width: 100%; min-width: 1000px; max-width: none; height: auto; margin: 0 auto; }
.diagram-scroll.tall img { width: 100%; min-width: 680px; height: auto; }
.diagram-scroll::before, .table-scroll::before { display: none; }
.diagram-caption { width: calc(100vw - 32px); max-width: 1100px; margin: 0 0 28px; color: var(--muted); font-size: 13px; }
.series-box { margin: 54px 0 0; padding: 24px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface); }
.series-box h2 { margin: 0 0 8px; padding: 0; border: 0; font-size: 21px; }
.series-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; margin: 18px 0 0; padding: 0; list-style: none; }
.series-grid a { display: block; height: 100%; padding: 12px; border: 1px solid var(--border); border-radius: 8px; text-decoration: none; }
.series-grid a[aria-current="page"] { border-color: var(--green); background: color-mix(in srgb, var(--green) 9%, transparent); color: var(--bright); }
.series-number { display: block; color: var(--muted); font: 11px/1.4 var(--mono); }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 28px 0 0; }
.pager a { padding: 16px; border: 1px solid var(--border); border-radius: 10px; text-decoration: none; }
.pager a:last-child { text-align: right; }
.pager-label { display: block; margin-bottom: 4px; color: var(--muted); font: 11px/1.4 var(--mono); }
.footer { margin-top: 64px; padding-top: 24px; border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; }

@media (max-width: 700px) {
  body { font-size: 15px; line-height: 1.85; }
  .shell { width: min(100% - 28px, 960px); padding-top: 30px; }
  .titlebar { padding-inline: 12px; }
  .article-body h2 { margin-top: 48px; }
  .series-grid, .pager { grid-template-columns: 1fr; }
  .pager a:last-child { text-align: left; }
  .diagram-scroll, .diagram-caption { width: calc(100vw - 28px); }
  .diagram-scroll::before {
    position: sticky; left: 0; z-index: 1; display: block; width: 100%; padding: 6px 10px;
    border-bottom: 1px solid #d0d7de; background: #f6f8fa; color: #57606a;
    content: '↔ 図は横にスクロールできます'; font: 11px/1.4 var(--sans);
  }
  .table-scroll::before {
    position: sticky; left: 0; display: block; width: 100%; padding: 5px 8px;
    border: 1px solid var(--border); border-bottom: 0; background: var(--surface);
    color: var(--muted); content: '↔ 表は横にスクロールできます'; font: 11px/1.4 var(--sans);
  }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { transition: none !important; } }