/* Bench Notes — layout: a narrow reading column with a quiet data rail, built
   around the Uno's own palette (solder-mask teal, copper traces, silkscreen white). */
:root {
  --bg: #f3f6f5;
  --surface: #ffffff;
  --sunk: #e8eeec;
  --fg: #15201d;
  --muted: #56645f;
  --line: #d3ddd9;
  --accent: #0a6b6c;
  --accent-soft: #d6ecea;
  --copper: #a8521c;
  --copper-soft: #f6e4d6;
  --ok: #2c7a3f;
  --warn: #9a5b00;
  --warn-soft: #fbf0dc;
  --code-bg: #10201d;
  --code-fg: #dfe9e5;
  --code-com: #7f9b93;
  --code-key: #7fd4c9;
  --code-str: #f0b27f;
  --code-num: #e7c86b;
  --code-fn: #a9c7ff;
  --font-display: "Archivo", "Arial Narrow", "Helvetica Neue", Arial, sans-serif;
  --font-body: "IBM Plex Sans", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --radius: 8px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d1513; --surface: #131e1b; --sunk: #0a110f; --fg: #e2ebe7; --muted: #9aaba5;
    --line: #253430; --accent: #5cc4bb; --accent-soft: #163633; --copper: #e5915a; --copper-soft: #3a2416;
    --ok: #6fca83; --warn: #e3ac55; --warn-soft: #33270f;
    --code-bg: #0a1210; --code-fg: #dbe6e2; --code-com: #6f8a83;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0d1513; --surface: #131e1b; --sunk: #0a110f; --fg: #e2ebe7; --muted: #9aaba5;
  --line: #253430; --accent: #5cc4bb; --accent-soft: #163633; --copper: #e5915a; --copper-soft: #3a2416;
  --ok: #6fca83; --warn: #e3ac55; --warn-soft: #33270f;
  --code-bg: #0a1210; --code-fg: #dbe6e2; --code-com: #6f8a83;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
:root { padding-top: env(safe-area-inset-top, 0px); padding-bottom: env(safe-area-inset-bottom, 0px); }
body {
  margin: 0; background: var(--bg); color: var(--fg);
  font: 16px/1.6 var(--font-body);
}
[hidden] { display: none !important; }
img, svg { max-width: 100%; }
a { color: var(--accent); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--copper); outline-offset: 2px; border-radius: 3px; }
code { font-family: var(--font-mono); font-size: .88em; background: var(--sunk); padding: .1em .35em; border-radius: 4px; }
h1, h2, h3 { font-family: var(--font-display); line-height: 1.15; text-wrap: balance; margin: 0; }
h1 { font-size: clamp(2rem, 1.4rem + 2.6vw, 3rem); font-weight: 800; font-stretch: 88%; letter-spacing: -.01em; }
h2 { font-size: 1.5rem; font-weight: 700; font-stretch: 92%; }
h3 { font-size: 1.1rem; font-weight: 700; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--surface); padding: 8px 12px; z-index: 50; }
.skip:focus { left: 16px; }

.wrap {
  max-width: 1160px; margin: 0 auto;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
}

/* ---------- header */
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 10; background: var(--surface); }
.site-head { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 20; background: var(--surface); border-bottom: 1px solid var(--line); }
.site-head .wrap { display: flex; align-items: center; gap: 20px; padding-block: 10px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--fg); text-decoration: none; }
.brand-mark { width: 30px; height: 30px; flex: none; }
.brand-name { font-family: var(--font-display); font-weight: 800; font-size: 1.25rem; font-stretch: 85%; letter-spacing: .01em; }
.brand-sub { display: block; font-size: .72rem; color: var(--muted); letter-spacing: .08em; text-transform: uppercase; line-height: 1; }
.main-nav { display: flex; gap: 4px; flex-wrap: wrap; }
.main-nav a { color: var(--fg); text-decoration: none; padding: 6px 10px; border-radius: 6px; font-weight: 500; font-size: .95rem; }
.main-nav a:hover, .main-nav a[aria-current="page"] { background: var(--accent-soft); color: var(--accent); }
.head-search { position: relative; margin-left: auto; flex: 1 1 240px; max-width: 340px; min-width: 0; }
.search-input {
  width: 100%; font: inherit; font-size: .95rem; color: var(--fg); background: var(--bg);
  border: 1px solid var(--line); border-radius: 999px; padding: 8px 14px 8px 36px;
}
.search-wrap { position: relative; }
.search-wrap svg { position: absolute; left: 12px; top: 50%; transform: translateY(-50%); width: 16px; height: 16px; stroke: var(--muted); fill: none; pointer-events: none; }
.search-input:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.drop {
  position: absolute; left: 0; right: 0; top: calc(100% + 6px); background: var(--surface);
  border: 1px solid var(--line); border-radius: var(--radius); box-shadow: 0 12px 32px rgb(0 0 0 / .14);
  max-height: 70vh; overflow: auto; z-index: 30; padding: 6px;
}
.drop a { display: block; padding: 8px 10px; border-radius: 6px; text-decoration: none; color: var(--fg); }
.drop a:hover, .drop a:focus { background: var(--accent-soft); outline: none; }
.drop .r-t { font-weight: 600; display: block; }
.drop .r-m { font-size: .8rem; color: var(--muted); }
.drop .empty { padding: 10px; color: var(--muted); font-size: .9rem; }
@media (max-width: 720px) {
  .head-search { order: 3; flex-basis: 100%; max-width: none; }
}

/* ---------- breadcrumbs */
.crumbs { font-size: .88rem; color: var(--muted); margin: 22px 0 12px; }
.crumbs ol { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 6px; }
.crumbs li + li::before { content: "›"; margin-right: 6px; color: var(--line); }
.crumbs a { color: var(--muted); }

/* ---------- chips */
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { display: inline-flex; align-items: center; gap: 4px; font-size: .78rem; font-weight: 600; padding: 3px 9px; border-radius: 999px; background: var(--sunk); color: var(--muted); letter-spacing: .01em; }
.chip.lvl-Beginner { background: var(--accent-soft); color: var(--accent); }
.chip.lvl-Intermediate { background: var(--copper-soft); color: var(--copper); }
.chip.lvl-Advanced { background: var(--fg); color: var(--bg); }

/* ---------- home */
.hero { padding-block: 44px 28px; display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: 40px; align-items: end; }
.hero h1 { font-size: clamp(2.6rem, 1.6rem + 4vw, 4.4rem); }
.hero .eyebrow { font-family: var(--font-mono); font-size: .8rem; color: var(--copper); letter-spacing: .06em; margin-bottom: 12px; display: block; }
.lede { font-size: 1.15rem; color: var(--muted); max-width: 60ch; margin: 14px 0 0; }
.hero-search .search-input { font-size: 1.05rem; padding: 14px 18px 14px 42px; }
.hero-search .search-wrap svg { left: 16px; width: 18px; height: 18px; }
.stats { display: flex; gap: 22px; margin-top: 14px; font-size: .9rem; color: var(--muted); flex-wrap: wrap; }
.stats b { font-family: var(--font-display); font-size: 1.4rem; color: var(--fg); margin-right: 4px; font-variant-numeric: tabular-nums; }
@media (max-width: 820px) { .hero { grid-template-columns: 1fr; gap: 20px; padding-block: 28px 12px; } }

.band { padding-block: 36px; }
.band + .band { border-top: 1px solid var(--line); }
.band-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; margin-bottom: 18px; flex-wrap: wrap; }
.band-head p { margin: 0; color: var(--muted); }

.path { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 0; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); overflow: hidden; }
.path li { min-width: 0; }
.path li + li { border-left: 1px solid var(--line); }
.path a { display: flex; flex-direction: column; gap: 6px; padding: 18px 16px; height: 100%; text-decoration: none; color: var(--fg); }
.path a:hover { background: var(--accent-soft); }
.path .step { font-family: var(--font-mono); font-size: .78rem; color: var(--copper); }
.path .p-t { font-family: var(--font-display); font-weight: 700; font-size: 1.05rem; line-height: 1.2; }
.path .p-s { font-size: .85rem; color: var(--muted); }
@media (max-width: 900px) {
  .path { grid-template-columns: 1fr; }
  .path li + li { border-left: 0; border-top: 1px solid var(--line); }
}

.topics { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.topic { display: grid; grid-template-rows: auto 1fr auto; gap: 8px; padding: 18px; border-radius: var(--radius); background: var(--surface); border: 1px solid var(--line); text-decoration: none; color: var(--fg); transition: border-color .15s; }
.topic:hover { border-color: var(--accent); }
.topic .t-h { display: flex; justify-content: space-between; align-items: baseline; gap: 10px; }
.topic h3 { font-size: 1.15rem; }
.topic .n { font-family: var(--font-mono); font-size: .8rem; color: var(--muted); font-variant-numeric: tabular-nums; }
.topic p { margin: 0; font-size: .9rem; color: var(--muted); }
.topic .t-list { font-size: .8rem; color: var(--accent); }
.topic.workshop { background: var(--copper-soft); border-color: transparent; }
.topic.workshop:hover { border-color: var(--copper); }

/* index + filters */
.filters { display: flex; flex-wrap: wrap; gap: 14px 22px; align-items: end; margin-bottom: 14px; }
.filters fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
.filters legend, .filters label.lab { font-size: .75rem; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); font-weight: 600; margin-bottom: 6px; display: block; }
.seg { display: flex; flex-wrap: wrap; gap: 4px; }
.seg input { position: absolute; opacity: 0; pointer-events: none; }
.seg label { cursor: pointer; padding: 6px 12px; border: 1px solid var(--line); border-radius: 999px; font-size: .88rem; background: var(--surface); }
.seg input:checked + label { background: var(--accent); color: var(--surface); border-color: var(--accent); }
.seg input:focus-visible + label { outline: 3px solid var(--copper); outline-offset: 2px; }
select { font: inherit; font-size: .92rem; color: var(--fg); background: var(--surface); border: 1px solid var(--line); border-radius: 6px; padding: 6px 10px; max-width: 100%; }
.reset { font: inherit; font-size: .88rem; background: none; border: 0; color: var(--accent); text-decoration: underline; cursor: pointer; padding: 6px 0; }
.count { font-size: .9rem; color: var(--muted); margin: 0 0 10px; font-variant-numeric: tabular-nums; }
.results { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.results li { border-bottom: 1px solid var(--line); }
.results a { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 4px 20px; padding: 14px 4px; text-decoration: none; color: var(--fg); }
.results a:hover .r-title { color: var(--accent); text-decoration: underline; }
.r-title { font-weight: 600; font-size: 1.02rem; }
.r-sum { grid-column: 1; font-size: .9rem; color: var(--muted); }
.r-meta { grid-column: 2; grid-row: 1 / span 2; align-self: center; justify-content: flex-end; max-width: 300px; }
.r-cat { font-size: .78rem; color: var(--copper); font-family: var(--font-mono); }
@media (max-width: 640px) { .results a { grid-template-columns: 1fr; } .r-meta { grid-column: 1; grid-row: auto; justify-content: flex-start; } }
.no-results { padding: 20px 4px; color: var(--muted); }

/* ---------- article */
.art-head { padding-bottom: 22px; border-bottom: 1px solid var(--line); margin-bottom: 26px; }
.art-head .lede { margin-bottom: 14px; }
.art-grid { display: grid; grid-template-columns: minmax(0, 1fr) 270px; gap: 48px; align-items: start; }
@media (max-width: 960px) { .art-grid { grid-template-columns: 1fr; gap: 24px; } .rail { order: -1; } }
.prose { max-width: 72ch; min-width: 0; }
.prose > section { margin-bottom: 38px; }
.prose h2 { margin-bottom: 12px; padding-top: 6px; }
.prose h2 .num { font-family: var(--font-mono); font-size: .8rem; color: var(--copper); font-weight: 500; display: block; letter-spacing: .05em; margin-bottom: 2px; }
.prose p, .prose ul, .prose ol { margin: 0 0 12px; }
.prose li { margin-bottom: 4px; }
.prose ul, .prose ol { padding-left: 1.3em; }
.formula { font-family: var(--font-mono); font-size: 1.1rem; background: var(--sunk); padding: 12px 16px; border-radius: 6px; display: inline-block; }
.rail { position: sticky; top: calc(env(safe-area-inset-top, 0px) + 80px); display: grid; gap: 16px; min-width: 0; }
@media (max-width: 960px) { .rail { position: static; } }
.glance { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; font-size: .9rem; }
.glance h2 { font-size: .78rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); font-family: var(--font-body); font-weight: 600; margin-bottom: 10px; }
.glance dl { margin: 0; display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 6px 12px; }
.glance dt { color: var(--muted); }
.glance dd { margin: 0; font-weight: 500; overflow-wrap: anywhere; }
.toc ol { margin: 0; padding-left: 1.1em; font-size: .9rem; }
.toc li { margin-bottom: 4px; }
.toc a { color: var(--fg); text-decoration: none; }
.toc a:hover { color: var(--accent); text-decoration: underline; }

.tbl-wrap { overflow-x: auto; margin: 0 0 14px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
.tbl { width: 100%; border-collapse: collapse; font-size: .92rem; }
.prose > section > .tbl { border: 1px solid var(--line); }
.tbl th, .tbl td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
.tbl th { font-size: .75rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); background: var(--sunk); }
.tbl tr:last-child td { border-bottom: 0; }
.tbl td:first-child { font-family: var(--font-mono); font-weight: 600; color: var(--copper); white-space: nowrap; }

figure { margin: 0 0 18px; }
.fig-box { overflow-x: auto; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px; }
.fig-box svg.dg { display: block; width: 100%; min-width: 540px; height: auto; }
figcaption { font-size: .85rem; color: var(--muted); margin-top: 6px; }

.parts { list-style: none; padding: 0 !important; }
.parts li { padding: 7px 0 7px 26px; border-bottom: 1px dashed var(--line); position: relative; margin: 0 !important; }
.parts li::before { content: ""; position: absolute; left: 4px; top: 15px; width: 10px; height: 10px; border: 2px solid var(--accent); border-radius: 2px; }

.note { border-radius: var(--radius); padding: 14px 16px; background: var(--warn-soft); border: 1px solid color-mix(in srgb, var(--warn) 30%, transparent); margin-bottom: 14px; }
.note > :last-child { margin-bottom: 0; }
.note-title { font-weight: 700; color: var(--warn); font-size: .85rem; text-transform: uppercase; letter-spacing: .06em; margin-bottom: 6px; display: block; }

.code-block { border-radius: var(--radius); overflow: hidden; background: var(--code-bg); margin-bottom: 14px; }
.code-bar { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 8px 10px 8px 16px; border-bottom: 1px solid rgb(255 255 255 / .08); }
.code-file { font-family: var(--font-mono); font-size: .82rem; color: var(--code-com); overflow-wrap: anywhere; }
.copy-btn { font: 600 .82rem var(--font-body); color: var(--code-bg); background: var(--code-key); border: 0; border-radius: 6px; padding: 6px 12px; cursor: pointer; flex: none; }
.copy-btn:hover { filter: brightness(1.1); }
.copy-btn.done { background: var(--code-num); }
pre.code { margin: 0; padding: 16px; overflow-x: auto; font: .86rem/1.6 var(--font-mono); color: var(--code-fg); tab-size: 2; }
pre.code code { background: none; padding: 0; font-size: inherit; color: inherit; }
.token.comment { color: var(--code-com); font-style: italic; }
.token.keyword, .token.boolean { color: var(--code-key); }
.token.string, .token.char { color: var(--code-str); }
.token.number { color: var(--code-num); }
.token.function { color: var(--code-fn); }
.token.macro, .token.directive, .token.property { color: var(--code-str); }
.token.operator, .token.punctuation { color: var(--code-fg); opacity: .8; }

.related { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 10px; }
.related a { display: block; padding: 12px 14px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); text-decoration: none; color: var(--fg); }
.related a:hover { border-color: var(--accent); }
.related .rl-t { font-weight: 600; display: block; }
.related .rl-c { font-size: .78rem; color: var(--muted); }

.pager { display: flex; justify-content: space-between; gap: 12px; margin: 10px 0 40px; flex-wrap: wrap; }
.pager a { flex: 1 1 240px; padding: 12px 14px; border: 1px solid var(--line); border-radius: var(--radius); text-decoration: none; color: var(--fg); background: var(--surface); }
.pager a:hover { border-color: var(--accent); }
.pager .pg-l { display: block; font-size: .75rem; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.pager .next { text-align: right; }

.calc { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; }
.calc label { font-size: .85rem; color: var(--muted); display: grid; gap: 4px; }
.calc input { font: inherit; color: var(--fg); background: var(--bg); border: 1px solid var(--line); border-radius: 6px; padding: 7px 10px; width: 100%; }
.calc output { grid-column: 1 / -1; font-family: var(--font-mono); font-size: 1rem; padding-top: 6px; border-top: 1px dashed var(--line); }

.topic-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.topic-list a { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 4px 16px; padding: 16px 18px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); text-decoration: none; color: var(--fg); }
.topic-list a:hover { border-color: var(--accent); }

/* ---------- footer */
.site-foot { border-top: 1px solid var(--line); background: var(--surface); margin-top: 40px; font-size: .88rem; color: var(--muted); }
.site-foot .wrap { padding-block: 26px; display: grid; grid-template-columns: minmax(0, 2fr) minmax(0, 1fr); gap: 24px; }
.site-foot p { margin: 0 0 8px; }
.site-foot nav { display: flex; flex-direction: column; gap: 4px; }
@media (max-width: 700px) { .site-foot .wrap { grid-template-columns: 1fr; } }

/* ---------- diagrams (theme-aware) */
.dg { font-family: var(--font-body); }
.dg-t, .dg-pin { fill: var(--fg); font-size: 14px; }
.dg-pin { font-family: var(--font-mono); font-size: 13px; }
.dg-pin.sm { font-size: 11px; }
.dg-cap { fill: var(--muted); font-size: 12.5px; }
.dg-blk { fill: var(--fg); font-weight: 700; font-size: 14px; }
.dg-via { fill: var(--copper); font-size: 12px; font-family: var(--font-mono); }
.dg-board { fill: var(--accent-soft); stroke: var(--accent); stroke-width: 1.5; }
.dg-part { fill: var(--sunk); stroke: var(--line); stroke-width: 1.5; }
.dg-dot { fill: var(--copper); }
.dg-wire { stroke: var(--copper); stroke-width: 2.5; fill: none; }
.dg-res { fill: var(--surface); stroke: var(--fg); stroke-width: 1.5; }
.dg-seg { fill: var(--sunk); stroke: var(--line); }
.dg-seg.on { fill: var(--copper); stroke: var(--copper); }
.dg-seglbl { fill: var(--fg); font-size: 13px; font-weight: 700; font-family: var(--font-mono); }
.dg-wave { fill: none; stroke: var(--accent); stroke-width: 2.5; stroke-linejoin: round; }
.dg-axis { stroke: var(--line); stroke-width: 1.5; }
.dg-arc { fill: none; stroke: var(--line); stroke-width: 2; }
.dg-arm { stroke: var(--accent); stroke-width: 3; stroke-linecap: round; }
.dg-badge { fill: var(--copper); }
.dg-badget { fill: var(--surface); font-size: 12px; font-weight: 700; }
.dg-zone { stroke: var(--line); }
.dg-zone.z0 { fill: var(--accent-soft); }
.dg-zone.z1 { fill: var(--copper-soft); }
.dg-zone.z2 { fill: var(--sunk); }
.dg-hole { fill: var(--sunk); stroke: var(--muted); stroke-width: 1; }
.dg-rail { stroke-width: 3; }
.dg-rail.p { stroke: var(--copper); }
.dg-rail.n { stroke: var(--accent); }
.dg-strip { stroke: var(--accent); stroke-width: 4; opacity: .35; }
.dg-gap { fill: var(--line); }

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