/* Vercel dark: black ground, Geist, 1px hairlines. Red marks what readers see
   today, blue marks the pull requests. */
:root {
  color-scheme: dark;
  --bg: #000000;
  --panel: #0a0a0a;
  --panel-2: #111111;
  --line: #262626;
  --line-2: #333333;
  --ink: #ededed;
  --ink-2: #a1a1a1;
  --ink-3: #808080;
  --red: #ff6166;
  --red-soft: #2a1213;
  --blue: #52a8ff;
  --blue-soft: #0b1b2e;
  --green: #62c073;
  --f-body: "Geist", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono: "Geist Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.6 var(--f-body); -webkit-font-smoothing: antialiased; }
a { color: var(--ink); text-underline-offset: 3px; text-decoration-color: var(--line-2); }
a:hover { text-decoration-color: var(--ink); }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; border-radius: 4px; }
h1, h2, h3 { margin: 0; line-height: 1.15; text-wrap: balance; letter-spacing: -0.02em; }
h1 { font-size: clamp(2.2rem, 5vw, 3.4rem); font-weight: 600; letter-spacing: -0.04em; }
h2 { font-size: clamp(1.6rem, 3.2vw, 2.1rem); font-weight: 600; letter-spacing: -0.03em; }
h3 { font-size: 1.1rem; font-weight: 600; }
p { margin: 0; }
code, .mono { font-family: var(--f-mono); font-size: 0.86em; }
:not(pre) > code { background: var(--panel-2); border: 1px solid var(--line); padding: 1px 5px; border-radius: 5px; }

.wrap { max-width: 1080px; margin: 0 auto; padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }
.prose { max-width: 680px; display: grid; gap: 14px; color: var(--ink-2); }
.prose strong { color: var(--ink); font-weight: 600; }
.stack { display: grid; gap: 16px; }
.eyebrow { font: 500 0.78rem/1 var(--f-mono); letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-3); }
.today { color: var(--red); }
.pr { color: var(--blue); }

/* Top bar */
.nav { position: sticky; top: 0; z-index: 10; background: rgba(0, 0, 0, 0.8); backdrop-filter: saturate(180%) blur(8px); border-bottom: 1px solid var(--line); }
.nav .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 56px; }
.brand { font-weight: 600; letter-spacing: -0.02em; text-decoration: none; display: inline-flex; align-items: center; gap: 10px; }
.brand i { width: 18px; height: 18px; border-radius: 50%; background: linear-gradient(135deg, var(--ink) 50%, var(--ink-3) 50%); }
.nav nav { display: flex; gap: 20px; font-size: 0.88rem; }
.nav nav a { color: var(--ink-2); text-decoration: none; }
.nav nav a:hover { color: var(--ink); }
@media (max-width: 560px) { .nav nav a.wide { display: none; } }

/* Sections */
.intro { padding-block: 56px 8px; max-width: 720px; font-size: 1.25rem; line-height: 1.5; color: var(--ink-2); text-wrap: pretty; }
.intro a { color: var(--ink); text-decoration-color: var(--ink-3); }
.name { font-size: clamp(2.6rem, 6vw, 4rem); letter-spacing: -0.045em; }
.tagline { font-size: 1.35rem; font-weight: 500; letter-spacing: -0.02em; color: var(--ink); }
.tagline code { font-size: 0.9em; }
section.part:last-child { border-bottom: 0; }
section.part { padding-block: 72px; display: grid; gap: 28px; border-bottom: 1px solid var(--line); }
.part-head { display: grid; gap: 14px; }
.sub-head { display: grid; gap: 10px; padding-top: 12px; }

/* Panels and demos */
.panel { border: 1px solid var(--line); border-radius: 12px; background: var(--panel); overflow: hidden; }
.panel-bar { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px; padding: 12px 16px; border-bottom: 1px solid var(--line); }
.tabs { display: flex; flex-wrap: wrap; gap: 6px; }
.tab { font: 500 0.82rem/1 var(--f-body); color: var(--ink-2); background: transparent; border: 1px solid transparent; border-radius: 6px; padding: 7px 10px; cursor: pointer; }
.tab:hover { color: var(--ink); }
.tab[aria-selected="true"] { color: var(--ink); background: var(--panel-2); border-color: var(--line-2); }
.controls { display: flex; align-items: center; gap: 10px; flex: 1 1 260px; justify-content: flex-end; }
.btn { font: 500 0.82rem/1 var(--f-body); color: var(--bg); background: var(--ink); border: 1px solid var(--ink); border-radius: 6px; padding: 8px 12px; cursor: pointer; min-width: 70px; }
.btn.ghost { color: var(--ink); background: transparent; border-color: var(--line-2); min-width: 0; }
.btn:hover { opacity: 0.88; }
input[type="range"] { flex: 1 1 140px; max-width: 260px; accent-color: var(--ink); }
.counter { font: 0.78rem/1 var(--f-mono); color: var(--ink-3); font-variant-numeric: tabular-nums; white-space: nowrap; }

.cols3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.cols3 > .col { padding: 16px; display: grid; gap: 10px; align-content: start; min-width: 0; }
.cols3 > .col + .col { border-left: 1px solid var(--line); }
.col-label { font: 500 0.75rem/1 var(--f-mono); letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-3); }
.col-label.today { color: var(--red); }
.col-label.pr { color: var(--blue); }
@media (max-width: 820px) { .cols3 { grid-template-columns: 1fr; } .cols3 > .col + .col { border-left: 0; border-top: 1px solid var(--line); } }

.raw { margin: 0; font: 0.8rem/1.7 var(--f-mono); white-space: pre-wrap; word-break: break-word; color: var(--ink-2); min-height: 6.8em; }
.raw .nl { color: var(--ink-3); }
.raw .trig { color: var(--red); background: var(--red-soft); outline: 1px solid var(--red); border-radius: 3px; }
.raw .caret { display: inline-block; width: 7px; height: 1.05em; vertical-align: -0.18em; background: var(--ink-2); margin-left: 1px; }
.reader { font-size: 0.95rem; line-height: 1.55; display: grid; gap: 8px; min-height: 6.8em; color: var(--ink); }
.reader p, .reader ul, .reader pre { margin: 0; }
.reader ul { padding-left: 1.2em; }
.reader a { color: var(--blue); text-decoration: underline; text-decoration-color: rgba(82, 168, 255, 0.4); }
.reader pre { background: var(--panel-2); border: 1px solid var(--line); border-radius: 6px; padding: 8px 10px; overflow-x: auto; font: 0.8rem/1.5 var(--f-mono); }
.reader .junk { color: var(--red); background: var(--red-soft); border-radius: 3px; padding: 0 2px; font: 0.82em var(--f-mono); }
.reader .gone { color: var(--red); border: 1px dashed var(--red); border-radius: 6px; padding: 6px 8px; font-size: 0.85rem; }
.added { font: 0.75rem/1.5 var(--f-mono); color: var(--ink-3); word-break: break-word; }
.added ins { text-decoration: none; color: var(--red); }
.added.ok ins { color: var(--blue); }
.added del { color: var(--red); }
.note { padding: 12px 16px; border-top: 1px solid var(--line); color: var(--ink-3); font-size: 0.85rem; }

/* Block diagrams */
.blocks { display: grid; gap: 4px; }
.blk { display: grid; grid-template-columns: 2.2em minmax(0, 1fr) auto; gap: 10px; align-items: start; padding: 7px 10px; border-radius: 6px; border: 1px solid var(--line); font: 0.78rem/1.6 var(--f-mono); }
.blk .no { color: var(--ink-3); }
.blk .txt { white-space: pre-wrap; word-break: break-word; min-width: 0; }
.blk .n { color: var(--ink-3); font-variant-numeric: tabular-nums; text-align: right; }
.blk.kept { background: var(--panel-2); color: var(--ink-3); border-color: transparent; }
.blk.rep { background: var(--blue-soft); border-color: var(--blue); }
.blk.rep .n { color: var(--blue); }
.blk.rep-today { background: var(--red-soft); border-color: var(--red); }
.blk.rep-today .n { color: var(--red); }
.blk.add { background: var(--red-soft); border-color: var(--red); color: var(--red); }
.cut { height: 0; border-top: 2px dashed var(--blue); margin: 4px 2px; }
.cut.bad { border-top-color: var(--red); }
.cut-label { font: 500 0.7rem/1 var(--f-mono); color: var(--blue); letter-spacing: 0.04em; text-transform: uppercase; margin: 2px 2px 0; }

.legend { display: flex; flex-wrap: wrap; gap: 8px 20px; font-size: 0.82rem; color: var(--ink-2); }
.legend span { display: inline-flex; align-items: center; gap: 8px; }
.legend i { width: 12px; height: 12px; border-radius: 3px; flex: none; }
.sw-kept { background: var(--panel-2); border: 1px solid var(--line-2); }
.sw-rep { background: var(--blue-soft); border: 1px solid var(--blue); }
.sw-today { background: var(--red-soft); border: 1px solid var(--red); }
.legend i.sw-line { height: 0; width: 18px; border-top: 2px dashed var(--blue); border-radius: 0; }

/* Live tail-repair demo */
.tail-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
.tail-grid > div { padding: 16px; min-width: 0; display: grid; gap: 14px; align-content: start; }
.tail-grid > div + div { border-left: 1px solid var(--line); }
@media (max-width: 820px) { .tail-grid { grid-template-columns: 1fr; } .tail-grid > div + div { border-left: 0; border-top: 1px solid var(--line); } }
.stat { display: grid; gap: 6px; }
.stat .k { font: 500 0.75rem/1 var(--f-mono); letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-3); }
.stat .v { font: 600 1.9rem/1 var(--f-body); letter-spacing: -0.03em; font-variant-numeric: tabular-nums; }
.stat .v small { font: 400 0.85rem var(--f-body); color: var(--ink-3); letter-spacing: 0; }
.meter { height: 8px; border-radius: 4px; background: var(--panel-2); overflow: hidden; }
.meter span { display: block; height: 100%; border-radius: 4px; transition: width 0.12s linear; }
@media (prefers-reduced-motion: reduce) { .meter span { transition: none; } }

/* Static comparisons */
.pair { display: grid; grid-template-columns: minmax(0, 1fr) 2.5rem minmax(0, 1fr); align-items: center; }
.pair .sym { justify-self: center; font: 600 1.4rem/1 var(--f-mono); }
@media (max-width: 760px) { .pair { grid-template-columns: 1fr; gap: 10px; } .pair .sym { justify-self: start; } }
.pairs { display: grid; gap: 20px; padding: 16px; }

.bars { display: grid; }
.bars .row { display: grid; grid-template-columns: 10em minmax(0, 1fr) minmax(0, 1fr); gap: 16px; align-items: center; padding: 14px 16px; }
.bars .row + .row { border-top: 1px solid var(--line); }
.bars .head { font: 500 0.75rem/1 var(--f-mono); letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-3); }
.bars .cell { display: grid; gap: 6px; min-width: 0; }
.bars .bar { height: 8px; border-radius: 4px; min-width: 4px; }
.bars .val { font: 0.82rem var(--f-mono); color: var(--ink-3); font-variant-numeric: tabular-nums; }
.bars .val b { color: var(--ink); font-weight: 600; }
.bars .upd b { display: block; font-weight: 600; }
.bars .upd span { color: var(--ink-3); font-size: 0.85rem; }
@media (max-width: 640px) { .bars .row { grid-template-columns: 1fr; gap: 10px; } .bars .row.head-row { display: none; } }

.tablewrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); }
table { border-collapse: collapse; width: 100%; font-size: 0.9rem; }
th, td { text-align: left; padding: 11px 16px; border-bottom: 1px solid var(--line); vertical-align: top; }
tr:last-child td { border-bottom: 0; }
th { font: 500 0.72rem/1.3 var(--f-mono); letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-3); }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }
td.mono { font: 0.8rem/1.6 var(--f-mono); word-break: break-word; }
td .junk { color: var(--red); background: var(--red-soft); border-radius: 3px; padding: 0 2px; }
.muted { color: var(--ink-3); }

.chart { padding: 16px; display: grid; gap: 12px; }
.chart svg { width: 100%; height: auto; display: block; }
.chart text { font-family: var(--f-mono); fill: var(--ink-3); font-size: 11px; }

.checks { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; max-width: 760px; }
.checks li { display: grid; grid-template-columns: 1.4em minmax(0, 1fr); gap: 10px; color: var(--ink-2); }
.checks li::before { content: "✓"; color: var(--green); font-weight: 600; }

pre.code { margin: 0; padding: 16px; overflow-x: auto; font: 0.8rem/1.7 var(--f-mono); color: var(--ink-2); }
pre.code .cm { color: var(--ink-3); }
pre.code .add { color: var(--blue); }
pre.code .rem { color: var(--ink-3); text-decoration: line-through; }


/* Before and after, in the demos' colors */
.ba { display: grid; max-width: 620px; margin-top: 6px; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.ba-row { display: grid; grid-template-columns: 6.5em minmax(0, 1fr); gap: 12px; align-items: baseline; padding: 12px 16px; color: var(--ink); }
.ba-row + .ba-row { border-top: 1px solid var(--line); }
.ba-k { display: inline-flex; align-items: center; gap: 8px; font: 500 0.75rem/1 var(--f-mono); letter-spacing: 0.04em; text-transform: uppercase; }
.ba-k::before { content: ""; width: 8px; height: 8px; border-radius: 2px; }
.ba-row.before { background: linear-gradient(90deg, var(--red-soft), transparent 60%); }
.ba-row.before .ba-k { color: var(--red); }
.ba-row.before .ba-k::before { background: var(--red); }
.ba-row.after { background: linear-gradient(90deg, var(--blue-soft), transparent 60%); }
.ba-row.after .ba-k { color: var(--blue); }
.ba-row.after .ba-k::before { background: var(--blue); }
@media (max-width: 480px) { .ba-row { grid-template-columns: 1fr; gap: 6px; } }

/* Card deck: the card in front scrolls with the page; the other card peeks
   out above it and comes to the front on click, Next, arrow keys or swipe. */
.switch { display: inline-flex; gap: 2px; padding: 3px; margin-top: 20px; border: 1px solid var(--line-2); border-radius: 8px; }
.switch button { font: 500 0.88rem/1 var(--f-body); color: var(--ink-2); background: transparent; border: 0; border-radius: 6px; padding: 8px 14px; cursor: pointer; }
.switch button:hover { color: var(--ink); }
.switch button[aria-selected="true"] { color: var(--bg); background: var(--ink); }
.deck { position: relative; margin-block: 72px 96px; }
.deck-card { background: #050505; border: 1px solid var(--line-2); border-radius: 16px; overflow: hidden; transform-origin: 50% 0; transition: transform 0.5s cubic-bezier(0.2, 0.8, 0.2, 1), opacity 0.5s; }
.deck-card.front { position: relative; z-index: 2; }
.deck-card.back { position: absolute; inset: 0; z-index: 1; transform: translateY(-46px) scale(0.95); opacity: 0.65; }
.deck-card.back:hover { opacity: 0.85; }
.card-strip { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 14px 24px; color: var(--ink); background: transparent; border: 0; border-bottom: 1px solid var(--line); font: 500 0.92rem/1.2 var(--f-body); text-align: left; cursor: pointer; }
.card-strip em { margin-left: 10px; font: 400 0.78rem var(--f-mono); font-style: normal; color: var(--ink-3); }
.card-strip .next { color: var(--ink-2); white-space: nowrap; }
.card-strip:hover .next { color: var(--ink); }
.deck-card.back .card-strip .next { visibility: hidden; }
.card-body { display: grid; gap: 28px; padding: 40px 32px 48px; }
@media (max-width: 640px) { .card-body { padding: 28px 16px 32px; } .card-strip { padding: 14px 16px; } }
@media (prefers-reduced-motion: reduce) { .deck-card { transition: none; } }