:root {
  --paper: #f2eee3; --ink: #1c1b19; --muted: #6a665c; --rule: #cfc8b6; --grid: rgba(28, 27, 25, .07);
  --blue: #1f3a93; --signal: #d9480f; --code-bg: #e9e4d5;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --mono: ui-monospace, "Cascadia Mono", Consolas, "Courier New", monospace;
  --sans: system-ui, "Segoe UI", sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root { --paper: #0f2236; --ink: #e8efe9; --muted: #9db0c4; --rule: #2c4660; --grid: rgba(232, 239, 233, .07);
    --blue: #9ec1ff; --signal: #ff9b5e; --code-bg: #0a1a2b; }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.6 var(--sans); }
a { color: var(--blue); text-underline-offset: 3px; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.1; margin: 0; letter-spacing: -.01em; }
pre { margin: 12px 0 0; padding: 12px 14px; background: var(--code-bg); border-left: 3px solid var(--blue); overflow-x: auto; font: 13px/1.5 var(--mono); }
code { font-family: var(--mono); }

.top, .hero, .sec, .foot { width: min(1080px, 100% - 40px); margin-inline: auto; }

.top { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 18px 0; border-bottom: 1px solid var(--rule); }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font: 600 18px var(--serif); }
.top nav { display: flex; align-items: center; gap: 22px; font: 13px var(--mono); text-transform: uppercase; letter-spacing: .06em; }
.top nav a { color: var(--muted); text-decoration: none; }
.top nav a:hover { color: var(--ink); }
.top nav .open { color: var(--ink); border: 1px solid var(--ink); padding: 6px 12px; }
.top nav .open:hover { background: var(--ink); color: var(--paper); }

.hero { display: grid; grid-template-columns: 1.05fr 1fr; gap: 56px; align-items: center; padding: 72px 0 80px; }
.label { margin: 0 0 18px; font: 13px var(--mono); text-transform: uppercase; letter-spacing: .1em; color: var(--signal); }
.hero h1 { font-size: clamp(38px, 5.4vw, 64px); }
.lead { margin: 22px 0 0; max-width: 34em; font-size: 19px; color: var(--ink); }
.cta { margin: 32px 0 0; display: flex; flex-wrap: wrap; align-items: center; gap: 12px 24px; }
.btn { display: inline-block; padding: 13px 22px; background: var(--ink); color: var(--paper); text-decoration: none; font: 600 15px var(--sans); border: 1px solid var(--ink); }
.btn:hover { background: var(--signal); border-color: var(--signal); color: #fff; }
.textlink { font-size: 15px; }
.btn.alt { background: transparent; color: var(--ink); }
.btn.alt:hover { background: var(--signal); color: #fff; }
.top nav .fb { color: var(--signal); border-bottom: 1px solid var(--signal); }
.feedback-box { margin-top: 44px; padding: 22px 24px; border: 1px solid var(--signal); background: color-mix(in srgb, var(--signal) 8%, transparent); max-width: 40em; }
.feedback-box h3 { font-size: 22px; }
.feedback-box p { margin: 8px 0 0; color: var(--muted); }

.hero-art { margin: 0; }
.hero-art svg { display: block; width: 100%; height: auto; background: var(--paper); border: 1px solid var(--rule); }
.hero-art figcaption { margin-top: 8px; font: 12px var(--mono); color: var(--muted); }
.grid path { stroke: var(--grid); stroke-width: 1; fill: none; }
.shape { fill: var(--paper); stroke: var(--ink); stroke-width: 2; stroke-linejoin: round; }
.shape.sel { stroke: var(--blue); stroke-dasharray: 6 4; }
.edge { stroke: var(--ink); stroke-width: 2; fill: none; }
.head { fill: var(--ink); }
.txt text { font: 600 17px var(--serif); fill: var(--ink); }
.dim path { stroke: var(--blue); stroke-width: 1.25; fill: none; }
.dim text { font: 12px var(--mono); fill: var(--blue); }
.stamp rect { fill: none; stroke: var(--signal); stroke-width: 3; }
.stamp text { font: 700 18px var(--mono); fill: var(--signal); letter-spacing: .14em; }

.sec { padding: 56px 0; border-top: 1px solid var(--rule); }
.sec-head { display: flex; align-items: baseline; gap: 18px; }
.no { font: 13px var(--mono); color: var(--signal); }
.sec h2 { font-size: clamp(28px, 3.4vw, 40px); }
.sec-intro { max-width: 40em; margin: 14px 0 0 calc(2ch + 18px); color: var(--muted); }

.rows { margin: 36px 0 0; }
.rows > div { display: grid; grid-template-columns: 240px 1fr; gap: 12px 40px; padding: 22px 0; border-top: 1px solid var(--rule); }
.rows dt { font: 600 21px var(--serif); }
.rows dd { margin: 0; max-width: 44em; }

.formats { display: grid; grid-template-columns: repeat(5, 1fr); margin-top: 36px; border-top: 1px solid var(--rule); }
.formats article { padding: 24px 18px 8px 0; min-width: 0; }
.formats article + article { padding-left: 18px; border-left: 1px solid var(--rule); }
.formats h3 { font-size: 24px; }
.formats p { margin: 8px 0 0; color: var(--muted); font-size: 15px; }
.note { margin: 28px 0 0; font: 13px var(--mono); color: var(--muted); }

.spec { list-style: none; margin: 32px 0 0; padding: 0; border-top: 1px solid var(--rule); }
.spec li { display: grid; grid-template-columns: 160px 1fr; gap: 24px; padding: 14px 0; border-bottom: 1px dotted var(--rule); }
.spec li span:first-child { font: 13px var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--muted); padding-top: 3px; }
.sec .cta { margin-top: 36px; }

details { border-top: 1px solid var(--rule); padding: 16px 0; max-width: 46em; }
details:last-of-type { border-bottom: 1px solid var(--rule); }
summary { cursor: pointer; font: 600 19px var(--serif); list-style: none; display: flex; justify-content: space-between; gap: 16px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; font: 20px var(--mono); color: var(--signal); }
details[open] summary::after { content: "–"; }
details p { margin: 12px 0 0; color: var(--muted); }
#faq .sec-head + details { margin-top: 32px; }

.foot { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; padding: 28px 0 48px; border-top: 1px solid var(--rule); font: 13px var(--mono); color: var(--muted); }
.foot nav { display: flex; flex-wrap: wrap; gap: 20px; }
.foot a { color: var(--muted); }

:focus-visible { outline: 3px solid var(--signal); outline-offset: 2px; }

@media (max-width: 860px) {
  .hero > *, .formats > *, .rows > div > * { min-width: 0; }
  .hero { grid-template-columns: 1fr; gap: 40px; padding: 44px 0 56px; }
  .top nav a:not(.open) { display: none; }
  .rows > div { grid-template-columns: 1fr; }
  .formats { grid-template-columns: 1fr; }
  .formats article, .formats article + article { padding: 20px 0; border-left: 0; border-top: 1px solid var(--rule); }
  .formats article:first-child { border-top: 0; }
  .spec li { grid-template-columns: 1fr; gap: 2px; }
  .sec-intro { margin-left: 0; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

.demo { display: grid; grid-template-columns: 1fr 1fr; gap: 0 24px; margin-top: 32px; }
.demo h3 { font: 13px var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--muted); font-weight: 400; }
.demo .loss { grid-column: 1 / -1; margin-top: 22px; border-left: 3px solid var(--signal); padding-left: 18px; }
.demo .loss h3 { color: var(--signal); }
.demo .loss ul { list-style: none; margin: 8px 0 0; padding: 0; }
.demo .loss li { display: grid; grid-template-columns: 70px minmax(0, 1fr); gap: 2px 14px; padding: 8px 0; border-top: 1px dotted var(--rule); }
.demo .loss b { font: 13px var(--mono); font-weight: 400; color: var(--muted); grid-row: span 2; }
.demo .loss code { font-size: 13px; overflow-wrap: anywhere; }
.demo .loss span { color: var(--muted); font-size: 15px; }
@media (max-width: 860px) { .demo { grid-template-columns: 1fr; } }

.matrix { margin-top: 32px; overflow-x: auto; }
.matrix table { width: 100%; border-collapse: collapse; font-size: 15px; }
.matrix caption { text-align: left; padding-bottom: 10px; font: 13px var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--muted); }
.matrix th, .matrix td { padding: 10px 14px 10px 0; text-align: left; border-top: 1px solid var(--rule); white-space: nowrap; }
.matrix thead th { font: 12px var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--muted); font-weight: 400; }
.matrix tbody th { font: 600 17px var(--serif); }
.matrix .no-conv { color: var(--muted); }
.matrix:focus-visible { outline: 3px solid var(--signal); outline-offset: 2px; }