/* ===== Design tokens ===== */
:root {
  color-scheme: light;
  --bg: #f7f8f7;
  --bg-elev: #ffffff;
  --bg-muted: #eef1f0;
  --fg: #1a1f1e;
  --fg-muted: #5b6663;
  --fg-faint: #8b9592;
  --line: #dfe4e2;
  --accent: #0f766e;
  --accent-strong: #0b5d57;
  --accent-soft: #d9f0ec;
  --accent-fg: #ffffff;
  --code-bg: #f1f4f3;
  --note: #2563eb; --note-bg: #e8f0fe;
  --tip: #15803d; --tip-bg: #e6f6ec;
  --warn: #b45309; --warn-bg: #fdf1e1;
  --imp: #7c3aed; --imp-bg: #f0e9fd;
  --shadow: 0 1px 2px rgba(20, 30, 28, 0.06), 0 4px 16px rgba(20, 30, 28, 0.06);
  --radius: 12px;
  --font-body: "Noto Sans JP", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --max: 1120px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #111615;
    --bg-elev: #191f1e;
    --bg-muted: #202827;
    --fg: #e6ebe9;
    --fg-muted: #a3aeaa;
    --fg-faint: #6f7a77;
    --line: #2b3432;
    --accent: #2dd4bf;
    --accent-strong: #5eead4;
    --accent-soft: #113c39;
    --accent-fg: #06201d;
    --code-bg: #151b1a;
    --note: #60a5fa; --note-bg: #14213a;
    --tip: #4ade80; --tip-bg: #10301c;
    --warn: #fbbf24; --warn-bg: #3a2a0f;
    --imp: #c4b5fd; --imp-bg: #2a1f4a;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.35);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #111615;
  --bg-elev: #191f1e;
  --bg-muted: #202827;
  --fg: #e6ebe9;
  --fg-muted: #a3aeaa;
  --fg-faint: #6f7a77;
  --line: #2b3432;
  --accent: #2dd4bf;
  --accent-strong: #5eead4;
  --accent-soft: #113c39;
  --accent-fg: #06201d;
  --code-bg: #151b1a;
  --note: #60a5fa; --note-bg: #14213a;
  --tip: #4ade80; --tip-bg: #10301c;
  --warn: #fbbf24; --warn-bg: #3a2a0f;
  --imp: #c4b5fd; --imp-bg: #2a1f4a;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.35);
}

/* ===== Base ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before, *::after { transition: none !important; animation: none !important; } }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
img { max-width: 100%; height: auto; }
button { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.container { max-width: var(--max); margin-inline: auto; padding-inline: 20px; }
.skip-link { position: absolute; left: -999px; top: 8px; background: var(--accent); color: var(--accent-fg); padding: 8px 12px; border-radius: 6px; z-index: 100; }
.skip-link:focus { left: 8px; }
h1, h2, h3, h4 { line-height: 1.35; text-wrap: balance; letter-spacing: -0.01em; margin: 0; }
.eyebrow { font-size: 12px; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); margin: 0 0 8px; }
.lead { color: var(--fg-muted); font-size: 17px; max-width: 65ch; margin: 8px 0 0; }

/* ===== Header ===== */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg-elev) 85%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; gap: 20px; height: 60px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--fg); font-weight: 700; font-size: 17px; }
.brand:hover { text-decoration: none; }
.brand-mark { display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 9px; background: var(--accent); color: var(--accent-fg); font-size: 13px; font-weight: 800; letter-spacing: .02em; }
.site-nav { display: flex; gap: 4px; margin-left: 8px; }
.site-nav a { padding: 6px 12px; border-radius: 8px; color: var(--fg-muted); font-size: 14px; font-weight: 500; }
.site-nav a:hover { background: var(--bg-muted); color: var(--fg); text-decoration: none; }
.header-actions { margin-left: auto; display: flex; gap: 4px; align-items: center; }
.icon-btn { display: inline-flex; align-items: center; gap: 8px; height: 38px; padding: 0 10px; border: 1px solid transparent; border-radius: 9px; background: transparent; cursor: pointer; color: var(--fg-muted); }
.icon-btn:hover { background: var(--bg-muted); color: var(--fg); }
.kbd-hint { font-size: 11px; color: var(--fg-faint); border: 1px solid var(--line); border-radius: 5px; padding: 1px 6px; font-family: var(--font-mono); }
.icon-moon { display: none; }
:root[data-theme="dark"] .icon-sun { display: none; }
:root[data-theme="dark"] .icon-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .icon-sun { display: none; }
  :root:not([data-theme="light"]) .icon-moon { display: block; }
}
.nav-toggle { display: none; }
@media (max-width: 720px) {
  .site-nav { display: none; position: absolute; left: 0; right: 0; top: 60px; flex-direction: column; background: var(--bg-elev); border-bottom: 1px solid var(--line); padding: 8px 12px 12px; margin: 0; box-shadow: var(--shadow); }
  .site-nav.open { display: flex; }
  .nav-toggle { display: inline-flex; }
  .kbd-hint { display: none; }
}

/* ===== Hero ===== */
.hero { padding-block: 56px 32px; border-bottom: 1px solid var(--line); background: linear-gradient(180deg, var(--bg-elev), var(--bg)); }
.hero h1 { font-size: clamp(28px, 4.5vw, 44px); font-weight: 700; }
.hero-search { margin-top: 24px; display: flex; align-items: center; gap: 12px; width: min(560px, 100%); padding: 12px 16px; border: 1px solid var(--line); border-radius: 12px; background: var(--bg-elev); color: var(--fg-faint); cursor: text; box-shadow: var(--shadow); text-align: left; }
.hero-search:hover { border-color: var(--accent); }
.hero-search span { flex: 1; }
.hero-search kbd { font-family: var(--font-mono); font-size: 11px; border: 1px solid var(--line); border-radius: 5px; padding: 1px 6px; }
.hero-stats { display: flex; gap: 28px; margin-top: 28px; }
.hero-stats div { display: flex; flex-direction: column; }
.hero-stats strong { font-size: 24px; font-variant-numeric: tabular-nums; line-height: 1.2; }
.hero-stats span { font-size: 12px; color: var(--fg-muted); }

/* ===== Sections ===== */
.section { padding-block: 40px; }
.section + .section { border-top: 1px solid var(--line); }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; margin-bottom: 20px; }
.section-head h2 { font-size: 22px; }
.section-head a { font-size: 14px; }

/* ===== Category cards ===== */
.cat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.cat-card { display: flex; align-items: flex-start; gap: 12px; padding: 16px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg-elev); color: var(--fg); transition: border-color .15s, transform .15s; }
.cat-card:hover { border-color: var(--accent); text-decoration: none; transform: translateY(-1px); }
.cat-icon { font-size: 22px; line-height: 1; margin-top: 2px; }
.cat-body { display: flex; flex-direction: column; gap: 2px; flex: 1; min-width: 0; }
.cat-label { font-weight: 700; }
.cat-desc { font-size: 13px; color: var(--fg-muted); line-height: 1.55; }
.cat-count { font-family: var(--font-mono); font-size: 13px; color: var(--fg-muted); background: var(--bg-muted); border-radius: 999px; padding: 2px 10px; }

/* ===== Article cards ===== */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; }
.card { display: flex; flex-direction: column; gap: 8px; padding: 18px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg-elev); transition: border-color .15s; }
.card:hover { border-color: var(--accent); }
.card-meta { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--fg-muted); flex-wrap: wrap; }
.card-meta time { font-variant-numeric: tabular-nums; }
.chip { display: inline-flex; align-items: center; gap: 4px; padding: 2px 10px; border-radius: 999px; font-size: 12px; font-weight: 600; }
.chip-cat { background: var(--accent-soft); color: var(--accent-strong); }
.chip-cat:hover { text-decoration: none; filter: brightness(.97); }
.card-title { font-size: 17px; font-weight: 700; }
.card-title a { color: var(--fg); }
.card-excerpt { margin: 0; font-size: 14px; color: var(--fg-muted); line-height: 1.7; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.card-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag { display: inline-flex; align-items: center; gap: 4px; font-size: 12px; color: var(--fg-muted); background: var(--bg-muted); border-radius: 6px; padding: 2px 8px; }
.tag:hover { color: var(--accent-strong); background: var(--accent-soft); text-decoration: none; }
.tag span { font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); }
.tag-cloud { display: flex; flex-wrap: wrap; gap: 8px; }
.tag-cloud-lg .tag { font-size: 14px; padding: 6px 12px; }
.empty { color: var(--fg-muted); }

/* ===== Generic page ===== */
.page { padding-block: 40px 64px; }
.page-head { margin-bottom: 24px; }
.page-head h1 { font-size: clamp(26px, 4vw, 34px); }
.page-head .count { font-size: 13px; color: var(--fg-faint); margin: 8px 0 0; font-variant-numeric: tabular-nums; }
.page.center { text-align: center; padding-block: 96px; }
.btn { display: inline-flex; align-items: center; gap: 6px; padding: 10px 18px; border-radius: 9px; background: var(--accent); color: var(--accent-fg); font-weight: 600; border: 1px solid transparent; cursor: pointer; }
.btn:hover { text-decoration: none; background: var(--accent-strong); }
.btn-ghost { background: transparent; color: var(--fg); border-color: var(--line); }
.btn-ghost:hover { background: var(--bg-muted); }

/* ===== Article ===== */
.article-layout { display: grid; grid-template-columns: minmax(0, 1fr) 240px; gap: 48px; padding-block: 32px 72px; }
@media (max-width: 960px) { .article-layout { grid-template-columns: minmax(0, 1fr); } .article-side { display: none; } }
.article { min-width: 0; max-width: 760px; }
.breadcrumb { display: flex; flex-wrap: wrap; gap: 6px; font-size: 13px; color: var(--fg-faint); margin-bottom: 16px; }
.breadcrumb span[aria-current] { color: var(--fg-muted); }
.article-header { padding-bottom: 20px; border-bottom: 1px solid var(--line); margin-bottom: 24px; display: flex; flex-direction: column; gap: 12px; }
.article-header h1 { font-size: clamp(26px, 4vw, 36px); }
.article-desc { margin: 0; color: var(--fg-muted); font-size: 16px; }
.article-meta { display: flex; flex-wrap: wrap; gap: 16px; font-size: 13px; color: var(--fg-muted); font-variant-numeric: tabular-nums; }
.article-side { position: sticky; top: 84px; align-self: start; max-height: calc(100vh - 100px); overflow: auto; }
.toc-inline { display: none; }
@media (max-width: 960px) { .toc-inline { display: block; margin-bottom: 24px; } }
.toc { font-size: 13px; padding: 14px 16px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg-elev); }
.toc-title { margin: 0 0 8px; font-weight: 700; font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--fg-faint); }
.toc ol { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 4px; }
.toc a { color: var(--fg-muted); display: block; line-height: 1.5; border-left: 2px solid transparent; padding-left: 10px; }
.toc a:hover, .toc a.active { color: var(--accent-strong); border-left-color: var(--accent); text-decoration: none; }
.toc-l3 { padding-left: 12px; }
.toc-l1 { display: none; }

.prose { font-size: 16px; }
.prose > :first-child { margin-top: 0; }
.prose h2 { font-size: 24px; margin: 48px 0 16px; padding-bottom: 8px; border-bottom: 1px solid var(--line); }
.prose h3 { font-size: 19px; margin: 32px 0 12px; }
.prose h4 { font-size: 16px; margin: 24px 0 8px; }
.prose h2 .anchor, .prose h3 .anchor, .prose h4 .anchor { float: right; opacity: 0; color: var(--fg-faint); font-weight: 400; margin-left: 8px; }
.prose h2:hover .anchor, .prose h3:hover .anchor, .prose h4:hover .anchor { opacity: 1; }
.prose p { margin: 0 0 1.2em; }
.prose ul, .prose ol { padding-left: 1.5em; margin: 0 0 1.2em; }
.prose li { margin: .3em 0; }
.prose li > ul, .prose li > ol { margin-bottom: 0; }
.prose strong { font-weight: 700; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 32px 0; }
.prose blockquote { margin: 0 0 1.2em; padding: 4px 18px; border-left: 3px solid var(--line); color: var(--fg-muted); }
.prose blockquote p:last-child { margin-bottom: 0; }
.prose code { font-family: var(--font-mono); font-size: .88em; background: var(--code-bg); border: 1px solid var(--line); border-radius: 5px; padding: .1em .4em; }
.prose pre { position: relative; margin: 0 0 1.4em; padding: 16px 18px; background: var(--code-bg); border: 1px solid var(--line); border-radius: 10px; overflow-x: auto; line-height: 1.6; }
.prose pre code { background: transparent; border: 0; padding: 0; font-size: 13.5px; }
.prose pre .hljs { background: transparent; padding: 0; }
.copy-btn { position: absolute; top: 8px; right: 8px; font-size: 12px; padding: 3px 8px; border-radius: 6px; border: 1px solid var(--line); background: var(--bg-elev); color: var(--fg-muted); cursor: pointer; opacity: 0; transition: opacity .15s; }
.prose pre:hover .copy-btn, .copy-btn:focus-visible { opacity: 1; }
.copy-btn.done { color: var(--accent-strong); border-color: var(--accent); }
.table-wrap { overflow-x: auto; margin: 0 0 1.4em; border: 1px solid var(--line); border-radius: 10px; }
.prose table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
.prose th, .prose td { padding: 10px 14px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.prose th { background: var(--bg-muted); font-weight: 700; white-space: nowrap; }
.prose tr:last-child td { border-bottom: 0; }
.prose img { border-radius: 8px; }
.callout { margin: 0 0 1.4em; padding: 14px 18px; border-radius: 10px; border: 1px solid; }
.callout p:last-child { margin-bottom: 0; }
.callout-title { font-weight: 700; font-size: 13px; letter-spacing: .06em; margin: 0 0 4px; }
.callout-note { background: var(--note-bg); border-color: color-mix(in srgb, var(--note) 40%, transparent); } .callout-note .callout-title { color: var(--note); }
.callout-tip { background: var(--tip-bg); border-color: color-mix(in srgb, var(--tip) 40%, transparent); } .callout-tip .callout-title { color: var(--tip); }
.callout-warning { background: var(--warn-bg); border-color: color-mix(in srgb, var(--warn) 40%, transparent); } .callout-warning .callout-title { color: var(--warn); }
.callout-important { background: var(--imp-bg); border-color: color-mix(in srgb, var(--imp) 40%, transparent); } .callout-important .callout-title { color: var(--imp); }

.post-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 48px; }
.post-nav-item { display: flex; flex-direction: column; gap: 4px; padding: 14px 16px; border: 1px solid var(--line); border-radius: 10px; background: var(--bg-elev); color: var(--fg); }
.post-nav-item:hover { border-color: var(--accent); text-decoration: none; }
.post-nav-item span { font-size: 12px; color: var(--fg-faint); }
.post-nav-item strong { font-size: 14px; }
.post-nav-item.next { text-align: right; }
@media (max-width: 560px) { .post-nav { grid-template-columns: 1fr; } .post-nav-item.next { text-align: left; } }
.related { margin-top: 48px; }
.related h2 { font-size: 20px; margin-bottom: 16px; }

/* ===== Footer ===== */
.site-footer { border-top: 1px solid var(--line); padding-block: 28px; font-size: 13px; color: var(--fg-muted); }
.footer-inner { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.footer-inner p { margin: 0; }

/* ===== Search dialog ===== */
.search-dialog { width: min(680px, calc(100% - 32px)); margin: 10vh auto; padding: 0; border: 1px solid var(--line); border-radius: 14px; background: var(--bg-elev); color: var(--fg); box-shadow: 0 20px 60px rgba(0,0,0,.25); }
.search-dialog::backdrop { background: rgba(10, 14, 13, .5); backdrop-filter: blur(2px); }
.search-box { display: flex; align-items: center; gap: 10px; padding: 12px 14px; border-bottom: 1px solid var(--line); margin: 0; color: var(--fg-muted); }
.search-box input { flex: 1; border: 0; outline: 0; background: transparent; font: inherit; font-size: 16px; color: var(--fg); }
.search-close { font-family: var(--font-mono); font-size: 11px; border: 1px solid var(--line); background: transparent; border-radius: 5px; padding: 2px 6px; color: var(--fg-faint); cursor: pointer; }
.search-results { max-height: 60vh; overflow: auto; padding: 8px; }
.search-hint { padding: 20px; text-align: center; color: var(--fg-faint); font-size: 14px; }
.search-item { display: block; padding: 10px 12px; border-radius: 8px; color: var(--fg); }
.search-item:hover, .search-item.active { background: var(--bg-muted); text-decoration: none; }
.search-item-title { font-weight: 700; font-size: 15px; }
.search-item-meta { font-size: 12px; color: var(--fg-faint); margin-top: 2px; }
.search-item-snippet { font-size: 13px; color: var(--fg-muted); margin-top: 4px; line-height: 1.6; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.search-item mark { background: var(--accent-soft); color: var(--accent-strong); border-radius: 3px; padding: 0 2px; }