/* zkFMI — one stylesheet. Dark first; light by system preference or the toggle. */
:root {
  --bg: #0a0e13;
  --bg-2: #10161e;
  --bg-3: #171f2a;
  --line: #22303f;
  --line-2: #2f3f52;
  --fg: #e8eef4;
  --fg-2: #aab7c5;
  --fg-3: #74879a;
  --accent: #5ee0c1;      /* teal: what is proved / checked */
  --accent-2: #f2b880;    /* amber: what is hidden */
  --accent-3: #9bb0ff;    /* periwinkle: mechanism */
  --danger: #ff8a80;
  --glow: rgba(94, 224, 193, 0.14);
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Hiragino Sans", "Noto Sans JP", sans-serif;
  --max: 1360px;
  --radius: 10px;
  color-scheme: dark;
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #fbfcfd; --bg-2: #f3f6f9; --bg-3: #e9eef4; --line: #d8dfe7; --line-2: #c4cdd8;
    --fg: #0e1622; --fg-2: #3b4959; --fg-3: #6b7a8c;
    --accent: #0c8c73; --accent-2: #b0611a; --accent-3: #3f56c9; --danger: #c0392b;
    --glow: rgba(12, 140, 115, 0.10);
    color-scheme: light;
  }
}
:root[data-theme="light"] {
  --bg: #fbfcfd; --bg-2: #f3f6f9; --bg-3: #e9eef4; --line: #d8dfe7; --line-2: #c4cdd8;
  --fg: #0e1622; --fg-2: #3b4959; --fg-3: #6b7a8c;
  --accent: #0c8c73; --accent-2: #b0611a; --accent-3: #3f56c9; --danger: #c0392b;
  --glow: rgba(12, 140, 115, 0.10);
  color-scheme: light;
}
:root[data-theme="dark"] {
  --bg: #0a0e13; --bg-2: #10161e; --bg-3: #171f2a; --line: #22303f; --line-2: #2f3f52;
  --fg: #e8eef4; --fg-2: #aab7c5; --fg-3: #74879a;
  --accent: #5ee0c1; --accent-2: #f2b880; --accent-3: #9bb0ff; --danger: #ff8a80;
  --glow: rgba(94, 224, 193, 0.14);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 16px/1.65 var(--sans); -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 2px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 3px; }
code, pre, kbd { font-family: var(--mono); font-size: 0.9em; }
code { background: var(--bg-3); padding: 0.1em 0.38em; border-radius: 4px; }
pre { position: relative; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 0.9rem 1rem; overflow-x: auto; line-height: 1.55; }
pre code { background: none; padding: 0; }
pre .copy { position: absolute; top: 6px; right: 6px; font: 500 0.7rem var(--mono); color: var(--fg-3); background: var(--bg-3); border: 1px solid var(--line); border-radius: 5px; padding: 0.15rem 0.5rem; cursor: pointer; opacity: 0; transition: opacity .15s; }
pre:hover .copy, pre .copy:focus-visible { opacity: 1; }
pre .copy:hover { color: var(--fg); }
pre.mermaid { background: var(--bg-2); text-align: center; padding: 1rem; overflow-x: auto; }
pre.mermaid svg { height: auto; }
kbd { background: var(--bg-3); border: 1px solid var(--line-2); border-bottom-width: 2px; border-radius: 4px; padding: 0 0.35em; font-size: 0.75em; color: var(--fg-2); }
h1, h2, h3, h4 { line-height: 1.22; letter-spacing: -0.015em; margin: 0 0 0.6em; font-weight: 700; }
h1 { font-size: 2.2rem; font-weight: 800; }
h2 { font-size: 1.45rem; margin-top: 2.6rem; padding-top: 0.5rem; border-top: 1px solid var(--line); }
h3 { font-size: 1.12rem; margin-top: 1.9rem; }
h5 { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.14em; color: var(--fg-3); margin: 1.2rem 0 0.4rem; font-weight: 600; }
p, ul, ol, table { margin: 0 0 1rem; }
li { margin: 0.28rem 0; }
blockquote { margin: 1.2rem 0; padding: 0.7rem 1.1rem; border-left: 3px solid var(--accent); background: var(--bg-2); color: var(--fg-2); border-radius: 0 6px 6px 0; }
hr { border: 0; border-top: 1px solid var(--line); margin: 2rem 0; }
strong { font-weight: 650; }
table { width: 100%; border-collapse: collapse; font-size: 0.93rem; }
.table-wrap { overflow-x: auto; margin-bottom: 1.2rem; border: 1px solid var(--line); border-radius: 8px; }
.table-wrap table { margin: 0; }
th, td { text-align: left; padding: 0.5rem 0.7rem; border-bottom: 1px solid var(--line); vertical-align: top; }
tr:last-child td { border-bottom: 0; }
th { color: var(--fg-2); font-weight: 600; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.07em; background: var(--bg-2); }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; font-family: var(--mono); font-size: 0.86em; white-space: nowrap; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 1rem; top: 1rem; background: var(--accent); color: var(--bg); padding: 0.5rem; z-index: 100; }
.muted { color: var(--fg-3); }

/* header */
.hdr { position: sticky; top: 0; z-index: 50; background: color-mix(in srgb, var(--bg) 82%, transparent); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.hdr .wrap { display: flex; align-items: center; height: 60px; gap: 1.5rem; }
.brand { display: inline-flex; align-items: center; gap: 0.45rem; font-weight: 800; font-size: 1.2rem; letter-spacing: -0.03em; color: var(--fg); }
.brand .logo { width: 26px; height: 26px; flex: none; }
.brand.small .logo { width: 22px; height: 22px; }
.brand .mark { color: var(--accent); font-family: var(--mono); font-weight: 600; letter-spacing: 0; }
.brand.small { font-size: 1rem; margin-bottom: 0.4rem; }
.topnav { margin-left: auto; display: flex; gap: 1.15rem; }
.topnav a { color: var(--fg-2); font-size: 0.92rem; font-weight: 500; }
.topnav a.on, .topnav a:hover { color: var(--fg); text-decoration: none; }
.topnav a.on { color: var(--accent); }
.topnav .gh { color: var(--fg-3); }
.tools { display: flex; align-items: center; gap: 0.4rem; }
.tools button { background: var(--bg-2); border: 1px solid var(--line); color: var(--fg-2); border-radius: 7px; height: 32px; display: inline-flex; align-items: center; gap: 0.4rem; padding: 0 0.55rem; cursor: pointer; font: 500 0.82rem var(--sans); }
.tools button:hover { color: var(--fg); border-color: var(--line-2); }
.search-btn kbd { margin-left: 0.2rem; }
.tools .lang { display: inline-flex; align-items: center; gap: 0.35rem; height: 32px; padding: 0 0.6rem; border: 1px solid var(--line); border-radius: 7px; background: var(--bg-2); color: var(--fg-2); font: 500 0.82rem var(--sans); text-decoration: none; }
.tools .lang:hover { color: var(--fg); border-color: var(--line-2); }
body.ja { --sans: "Inter", "Noto Sans JP", "Hiragino Sans", "Hiragino Kaku Gothic ProN", -apple-system, BlinkMacSystemFont, sans-serif; }
body.ja h1, body.ja h2, body.ja h3 { letter-spacing: 0; }
.tools .menu { display: none; font-size: 1.2rem; }
@media (max-width: 900px) {
  .topnav { display: none; position: absolute; top: 60px; left: 0; right: 0; background: var(--bg); border-bottom: 1px solid var(--line); flex-direction: column; padding: 0.8rem 1.25rem; gap: 0.6rem; }
  .topnav.open { display: flex; }
  .tools .menu { display: inline-flex; }
  .search-btn span, .search-btn kbd { display: none; }
  .tools .lang span { display: none; }
}

/* search */
.search-modal[hidden] { display: none; }
.search-modal { position: fixed; inset: 0; z-index: 90; background: color-mix(in srgb, var(--bg) 70%, transparent); backdrop-filter: blur(4px); display: flex; align-items: flex-start; justify-content: center; padding: 8vh 1rem; }
.search-box { width: min(680px, 100%); background: var(--bg-2); border: 1px solid var(--line-2); border-radius: 12px; box-shadow: 0 30px 80px rgba(0,0,0,0.45); overflow: hidden; }
.search-box input { width: 100%; font: 1.05rem var(--sans); padding: 0.9rem 1.1rem; border: 0; border-bottom: 1px solid var(--line); background: transparent; color: var(--fg); outline: none; }
.search-results { list-style: none; margin: 0; padding: 0.3rem 0; max-height: 55vh; overflow-y: auto; }
.search-results li a { display: block; padding: 0.55rem 1.1rem; color: var(--fg); text-decoration: none; }
.search-results li a:hover, .search-results li.on a { background: var(--bg-3); }
.search-results .st { font-weight: 600; font-size: 0.95rem; }
.search-results .st small { color: var(--accent); font-weight: 500; margin-left: 0.4rem; }
.search-results .sx { color: var(--fg-3); font-size: 0.82rem; display: block; margin-top: 0.1rem; }
.search-results mark { background: color-mix(in srgb, var(--accent-2) 40%, transparent); color: inherit; border-radius: 2px; padding: 0 1px; }
.search-hint { margin: 0; padding: 0.5rem 1.1rem; font-size: 0.75rem; color: var(--fg-3); border-top: 1px solid var(--line); }

/* landing */
.hero { position: relative; padding: 5.5rem 0 3.5rem; overflow: hidden; }
.hero::before { content: ""; position: absolute; inset: 0; background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px); background-size: 48px 48px; opacity: 0.35; mask-image: radial-gradient(ellipse at 30% 20%, #000 0%, transparent 65%); -webkit-mask-image: radial-gradient(ellipse at 30% 20%, #000 0%, transparent 65%); pointer-events: none; }
.hero::after { content: ""; position: absolute; width: 60vw; height: 60vw; max-width: 720px; max-height: 720px; right: -20vw; top: -30vw; background: radial-gradient(closest-side, var(--glow), transparent); pointer-events: none; }
.hero .wrap { position: relative; display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: 3rem; align-items: center; }
.hero .eyebrow { font-family: var(--mono); color: var(--accent); font-size: 0.78rem; letter-spacing: 0.12em; text-transform: uppercase; margin-bottom: 1.1rem; }
.hero h1 { font-size: clamp(2.2rem, 4.6vw, 3.6rem); margin-bottom: 1.2rem; letter-spacing: -0.03em; line-height: 1.08; }
.hero h1 em { font-style: normal; color: var(--accent); }
.hero .lede { font-size: 1.15rem; color: var(--fg-2); max-width: 58ch; }
.hero .cta { display: flex; gap: 0.7rem; flex-wrap: wrap; margin-top: 1.8rem; }
.hero-art { justify-self: end; width: 100%; max-width: 520px; }
.hero-art svg { width: 100%; height: auto; display: block; }
@media (max-width: 900px) { .hero .wrap { grid-template-columns: 1fr; } .hero-art { justify-self: start; max-width: 560px; } }
.btn { display: inline-flex; align-items: center; gap: 0.4rem; padding: 0.62rem 1.1rem; border-radius: 8px; font-weight: 600; border: 1px solid var(--line-2); color: var(--fg); background: var(--bg-2); font-size: 0.95rem; }
.btn.primary { background: var(--accent); color: #06110e; border-color: var(--accent); }
.btn:hover { text-decoration: none; filter: brightness(1.08); }
.strip { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--bg-2); }
.strip .wrap { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 1rem 2rem; padding: 1.3rem 1.25rem; }
.stat { font-family: var(--mono); }
.stat b { display: block; font-size: 1.55rem; color: var(--fg); font-weight: 600; letter-spacing: -0.02em; }
.stat span { color: var(--fg-3); font-size: 0.78rem; line-height: 1.4; display: block; margin-top: 0.15rem; }
section.block { padding: 3.4rem 0 1rem; }
section.block h2 { border: 0; margin-top: 0; font-size: 1.75rem; letter-spacing: -0.02em; }
section.block > .wrap > p:first-of-type, .intro { max-width: 70ch; color: var(--fg-2); font-size: 1.02rem; }
.grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); }
.grid.two { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.card { display: block; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.15rem 1.25rem; color: inherit; transition: border-color .15s, transform .15s; }
a.card:hover { text-decoration: none; border-color: var(--line-2); transform: translateY(-1px); }
.card h3 { margin-top: 0; font-size: 1.05rem; }
.card p { color: var(--fg-2); font-size: 0.95rem; margin-bottom: 0.4rem; }
.card ul { padding-left: 1.1rem; color: var(--fg-2); font-size: 0.95rem; }
.card .tag { font-family: var(--mono); font-size: 0.7rem; color: var(--fg-3); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 0.35rem; }
.card.hidden { border-top: 3px solid var(--accent-2); }
.card.checked { border-top: 3px solid var(--accent-3); }
.card.proved { border-top: 3px solid var(--accent); }
.three { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.col h3 { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.12em; margin: 0 0 0.6rem; }
.col.h h3 { color: var(--accent-2); } .col.m h3 { color: var(--accent-3); } .col.c h3 { color: var(--accent); }
.col ul { list-style: none; padding: 0; }
.col li { padding: 0.5rem 0.85rem; border: 1px solid var(--line); border-radius: 7px; margin: 0.4rem 0; background: var(--bg-2); font-size: 0.95rem; }
.col.h li { border-left: 3px solid var(--accent-2); } .col.m li { border-left: 3px solid var(--accent-3); } .col.c li { border-left: 3px solid var(--accent); }
.honest { border: 1px solid color-mix(in srgb, var(--danger) 45%, var(--line)); background: color-mix(in srgb, var(--danger) 6%, var(--bg-2)); border-radius: var(--radius); padding: 1.1rem 1.3rem; }
.honest h3 { margin-top: 0; color: var(--danger); }
.paths { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.paths .card ol { padding-left: 1.2rem; margin: 0.4rem 0 0; color: var(--fg-2); font-size: 0.95rem; }
.compare th:first-child, .compare td:first-child { white-space: nowrap; }
.cmp-legend { display: flex; flex-wrap: wrap; gap: 0.5rem 1.4rem; font-size: 0.82rem; margin: 0 0 1rem; }
.cmp-legend .v::before, .cmp .v dt::before { content: ""; display: inline-block; width: 0.6rem; height: 0.6rem; border-radius: 2px; margin-right: 0.45rem; vertical-align: middle; background: currentColor; }
.cmpgrid { display: grid; gap: 0.9rem; margin: 0 0 1.4rem; }
.cmp { border: 1px solid var(--line); border-radius: 8px; background: var(--bg); padding: 0.9rem 1.1rem 0.2rem; }
.cmp.self { border-color: var(--accent); background: var(--bg-2); }
.cmp header { display: flex; flex-wrap: wrap; align-items: baseline; gap: 0.3rem 1rem; margin-bottom: 0.6rem; }
.cmp h4 { margin: 0; font-size: 1.05rem; }
.cmp .stage { font-family: var(--mono); font-size: 0.75rem; color: var(--fg-3); }
.cmp .verdicts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.5rem 1.2rem; margin: 0 0 0.7rem; }
@media (min-width: 1100px) { .cmp .verdicts { grid-template-columns: repeat(4, minmax(0, 1fr)); } }
@media (max-width: 560px) { .cmp .verdicts { grid-template-columns: 1fr; } }
.cmp .v { border-left: 2px solid currentColor; padding-left: 0.6rem; }
.cmp .v dt { font-family: var(--mono); font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em; font-weight: 600; margin-bottom: 0.15rem; }
.cmp .v dd { margin: 0; font-size: 0.86rem; color: var(--fg-2); font-weight: 400; line-height: 1.45; }
.cmp .diff { font-size: 0.92rem; color: var(--fg); margin: 0 0 0.8rem; border-top: 1px dashed var(--line); padding-top: 0.6rem; }
.cmp .difflabel { font-family: var(--mono); font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--accent); margin-right: 0.4rem; }
.yes { color: var(--accent); font-weight: 600; } .no { color: var(--fg-3); } .part { color: var(--accent-2); font-weight: 600; }

/* docs layout */
html { --side-w: 230px; --toc-w: 210px; --rail-w: 34px; }
html.side-closed { --side-w: var(--rail-w); }
html.toc-closed { --toc-w: var(--rail-w); }
.doclayout { display: grid; grid-template-columns: var(--side-w) minmax(0, 1fr) var(--toc-w); gap: 2rem; padding-top: 2rem; padding-bottom: 4rem; transition: grid-template-columns .15s ease; }
.rail-toggle { display: inline-flex; align-items: center; gap: 0.4rem; background: var(--bg-2); border: 1px solid var(--line); color: var(--fg-3); border-radius: 7px; padding: 0.25rem 0.5rem; font: 500 0.75rem var(--sans); cursor: pointer; margin-bottom: 0.6rem; }
.rail-toggle:hover { color: var(--fg); border-color: var(--line-2); }
.rail-toggle .ico { font-size: 0.8rem; line-height: 1; }
html.side-closed .side .side-body, html.toc-closed .toc .toc-body { display: none; }
html.side-closed .side .rail-toggle .lbl, html.toc-closed .toc .rail-toggle .lbl { display: none; }
html.side-closed .side .rail-toggle, html.toc-closed .toc .rail-toggle { padding: 0.35rem 0.45rem; }
html.side-closed .side .rail-toggle .ico { transform: rotate(180deg); }
html.toc-closed .toc .rail-toggle .ico { transform: rotate(0deg); }
html.toc-open .toc .rail-toggle .ico { transform: rotate(180deg); }
.toc .rail-toggle { margin-left: -0.9rem; }
html.toc-closed .toc { border-left-color: transparent; }
.side, .toc { position: sticky; top: 80px; align-self: start; max-height: calc(100vh - 100px); overflow-y: auto; font-size: 0.9rem; scrollbar-width: thin; }
.side ul, .toc ul { list-style: none; padding: 0; margin: 0 0 0.6rem; }
.side a, .toc a { color: var(--fg-2); display: block; padding: 0.22rem 0; }
.side a.on { color: var(--accent); font-weight: 600; }
.side a:hover, .toc a:hover { color: var(--fg); text-decoration: none; }
.toc { font-size: 0.82rem; border-left: 1px solid var(--line); padding-left: 0.9rem; }
.toc a { padding: 0.2rem 0; color: var(--fg-3); }
.toc a.on { color: var(--accent); }
.doc { min-width: 0; }
.doc article { max-width: 104ch; }
.doc h1 { font-size: 2.05rem; }
.doc .lede { font-size: 1.12rem; color: var(--fg-2); margin-bottom: 1.6rem; }
.doc h2 a.anchor { color: var(--fg-3); margin-left: 0.4rem; font-weight: 400; opacity: 0; font-size: 0.9em; }
.doc h2:hover a.anchor { opacity: 1; }
.note { border: 1px solid var(--line); background: var(--bg-2); border-left: 3px solid var(--accent-3); border-radius: 6px; padding: 0.75rem 1rem; margin: 1.1rem 0; font-size: 0.95rem; }
.note.warn { border-left-color: var(--accent-2); }
.note.stop { border-left-color: var(--danger); }
.src { font-size: 0.78rem; color: var(--fg-3); font-family: var(--mono); margin-top: -0.6rem; margin-bottom: 1.3rem; line-height: 1.5; }
.kv { display: grid; grid-template-columns: max-content 1fr; gap: 0.35rem 1.2rem; font-size: 0.95rem; margin-bottom: 1rem; }
.kv dt { color: var(--fg-3); font-family: var(--mono); font-size: 0.82rem; padding-top: 0.15rem; }
.kv dd { margin: 0; }
@media (max-width: 600px) { .kv { grid-template-columns: 1fr; gap: 0.1rem; } .kv dd { margin-bottom: 0.5rem; } }
.pill { display: inline-block; font-family: var(--mono); font-size: 0.7rem; padding: 0.1rem 0.5rem; border-radius: 999px; border: 1px solid var(--line-2); color: var(--fg-2); vertical-align: middle; white-space: nowrap; }
.pill.ok { border-color: var(--accent); color: var(--accent); }
.pill.part { border-color: var(--accent-2); color: var(--accent-2); }
.pill.no { border-color: var(--danger); color: var(--danger); }
.next { display: flex; justify-content: space-between; gap: 1rem; margin-top: 3rem; padding-top: 1rem; border-top: 1px solid var(--line); font-size: 0.95rem; }
.fig { margin: 1.4rem 0; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 0.8rem 0.8rem 0.6rem; }
.fig figcaption { font-size: 0.82rem; color: var(--fg-3); padding: 0.4rem 0.4rem 0; line-height: 1.5; }
svg.chart { width: 100%; height: auto; display: block; font-family: var(--mono); }
svg.chart .ct { font: 600 13px var(--sans); fill: var(--fg); }
svg.chart .cl { font-size: 10.5px; fill: var(--fg-3); }
svg.chart .cv { fill: var(--fg-2); }
svg.chart .cg { stroke: var(--line); stroke-width: 1; }
.faq details { border: 1px solid var(--line); border-radius: 8px; background: var(--bg-2); margin: 0.6rem 0; padding: 0 1rem; }
.faq summary { cursor: pointer; font-weight: 600; padding: 0.75rem 0; list-style: none; display: flex; justify-content: space-between; gap: 1rem; }
.faq summary::after { content: "+"; color: var(--fg-3); font-family: var(--mono); }
.faq details[open] summary::after { content: "−"; }
.faq details p, .faq details ul { margin-top: 0; color: var(--fg-2); }
.timeline { list-style: none; padding: 0; margin: 0; border-left: 2px solid var(--line-2); }
.timeline li { position: relative; padding: 0 0 1.2rem 1.4rem; }
.timeline li::before { content: ""; position: absolute; left: -7px; top: 0.4rem; width: 12px; height: 12px; border-radius: 50%; background: var(--bg); border: 2px solid var(--accent); }
.timeline li.done::before { background: var(--accent); }
.timeline li.blocked::before { border-color: var(--danger); }
.timeline h4 { margin: 0 0 0.2rem; font-size: 1rem; }
.timeline p { margin: 0; color: var(--fg-2); font-size: 0.95rem; }
@media (max-width: 1050px) { .doclayout { grid-template-columns: var(--side-w) minmax(0, 1fr); } .toc { display: none; } }
.side-toggle { display: none; width: 100%; text-align: left; background: var(--bg-2); border: 1px solid var(--line); color: var(--fg); border-radius: 8px; padding: 0.6rem 0.9rem; font: 600 0.92rem var(--sans); cursor: pointer; }
.side-toggle span { float: right; color: var(--fg-3); transition: transform .15s; }
.side.open .side-toggle span { transform: rotate(180deg); }
@media (max-width: 760px) {
  .doclayout { grid-template-columns: 1fr; gap: 1.2rem; }
  .side { position: static; max-height: none; border-bottom: 1px solid var(--line); padding-bottom: 0.8rem; }
  .side-toggle { display: block; }
  .side .rail-toggle { display: none; }
  .side-body, html.side-closed .side .side-body { display: none; }
  .side.open .side-body, html.side-closed .side.open .side-body { display: block; }
}

/* footer */
.foot { border-top: 1px solid var(--line); background: var(--bg-2); padding: 2.5rem 0; margin-top: 2rem; font-size: 0.92rem; color: var(--fg-2); }
.foot .cols { display: grid; gap: 2rem; grid-template-columns: 2fr 1.3fr 1fr; }
.foot h4 { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--fg-3); margin-bottom: 0.5rem; }
.foot ul { list-style: none; padding: 0; }
.foot .repos .muted { font-family: var(--mono); font-size: 0.72rem; }
.foot .muted { color: var(--fg-3); font-size: 0.85rem; }
.foot .disclaimer { margin-top: 2rem; padding-top: 1rem; border-top: 1px solid var(--line); color: var(--fg-3); font-size: 0.82rem; }
@media (max-width: 700px) { .foot .cols { grid-template-columns: 1fr; } }

/* ja */
body.ja { font-feature-settings: "palt"; }
body.ja .hero h1 { letter-spacing: 0; line-height: 1.25; }
@media print { .hdr, .side, .toc, .foot, .search-modal { display: none !important; } .doclayout { display: block; } body { background: #fff; color: #000; } }

/* Long technical relations retain readable text and locally scrollable math. */
.technical-equation{max-width:100%;overflow-x:auto;overflow-y:hidden;padding:1rem 0}
.technical-equation .katex-display{margin:.5rem 0;text-align:left}
.technical-relations{display:grid;grid-template-columns:9rem minmax(0,1fr);gap:.7rem 1.2rem;margin:1.5rem 0 2rem}
.technical-relations dt{font-weight:650;color:var(--text)}
.technical-relations dd{margin:0;line-height:1.8;overflow-wrap:anywhere}
@media(max-width:700px){.technical-relations{grid-template-columns:1fr;gap:.3rem}.technical-relations dd{margin-bottom:.9rem}}