:root {
  --bg: #f7f6f2;
  --text: #1c1c1a;
  --muted: #6e6c66;
  --line: #d9d6cd;
  --field: #ffffff;
  --link: #1d4ed8;
  --matched: #2fbf71;
  --dets: #ff9f43;
  --grid: #7cc7ff;
  --names: #ffe27a;
  --foot: #ff5a5a;
  --cam: #4fb3ff;
  --serif: "Source Serif 4", Georgia, serif;
  --sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141413;
    --text: #e8e6e0;
    --muted: #9b988f;
    --line: #34332f;
    --field: #1d1c1a;
    --link: #8ab4ff;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body { background: var(--bg); color: var(--text); font: 16px/1.55 var(--sans); }
a, .link { color: var(--link); text-decoration: none; }
a:hover, .link:hover { text-decoration: underline; }
.link { background: none; border: 0; padding: 0; font: inherit; cursor: pointer; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.2; }
h1 { font-size: clamp(30px, 4.5vw, 44px); margin: 0 0 12px; letter-spacing: -.01em; }
h2 { font-size: 20px; margin: 0 0 10px; }
.muted { color: var(--muted); font-weight: 400; }
[hidden] { display: none !important; }
code { font-family: var(--mono); font-size: .9em; }

.top { display: flex; justify-content: space-between; align-items: baseline; gap: 16px;
  max-width: 1180px; margin: 0 auto; padding: 18px 24px; border-bottom: 1px solid var(--line); }
.brand { font-family: var(--serif); font-size: 19px; font-weight: 600; color: var(--text); }
.brand:hover { text-decoration: none; }
.top nav { display: flex; gap: 20px; font-size: 15px; }
main { max-width: 1180px; margin: 0 auto; padding: 0 24px 48px; }

/* start */
#view-start { max-width: 760px; margin: 0 auto; padding-top: 56px; }
.lead { color: var(--muted); font-size: 18px; margin: 0 0 28px; }
.drop { display: flex; flex-direction: column; align-items: center; gap: 4px; padding: 48px 20px; cursor: pointer;
  border: 1.5px dashed var(--muted); border-radius: 6px; background: var(--field); text-align: center; }
.drop span { font-size: 17px; }
.drop small { color: var(--muted); }
.drop:hover, .drop:focus-visible, .drop.over { border-color: var(--text); outline: none; }
.offline { color: #b42318; font-size: 14px; margin: 10px 0 0; }
.options { margin-top: 14px; font-size: 15px; }
.options summary { cursor: pointer; color: var(--muted); }
.opt { display: grid; grid-template-columns: 1fr 1fr; gap: 12px 24px; padding: 14px 0 4px; }
.opt label { display: flex; flex-direction: column; gap: 4px; color: var(--muted); font-size: 14px; }
.opt .row { display: flex; align-items: center; gap: 8px; color: var(--text); }
.opt .check { flex-direction: row; align-items: center; gap: 8px; color: var(--text); }
input[type=number], select { font: inherit; font-size: 15px; color: var(--text); background: var(--field);
  border: 1px solid var(--line); border-radius: 4px; padding: 6px 8px; }
input[type=number] { width: 110px; }
input[type=range] { flex: 1; accent-color: var(--text); }
input[type=checkbox] { accent-color: var(--text); }
.small-head { font-size: 15px; font-family: var(--sans); font-weight: 600; color: var(--muted); margin: 40px 0 10px; }
.examples { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.example { padding: 0; border: 0; background: none; color: inherit; font: inherit; text-align: left; cursor: pointer; }
.example img { display: block; width: 100%; aspect-ratio: 1; object-fit: cover; background: #000; border-radius: 3px; }
.example span { display: block; font-size: 13.5px; margin-top: 6px; }
.example:hover span, .example:focus-visible span { text-decoration: underline; }
.example:focus-visible { outline: none; }

/* working */
.work { text-align: center; padding: 56px 0; }
.work img { max-width: min(560px, 100%); max-height: 56vh; display: block; margin: 0 auto 16px; background: #000; opacity: .9; }
.work p { font-family: var(--mono); margin: 0 0 8px; }

/* result */
.bar { display: flex; justify-content: space-between; padding: 18px 0 12px; font-size: 15px; }
.bar span { display: flex; gap: 18px; }
.result { display: grid; grid-template-columns: minmax(0, 1fr) 330px; gap: 28px; align-items: start; }
.viewer { position: relative; height: min(70vh, 720px); min-height: 340px; background: #000; overflow: hidden;
  cursor: crosshair; touch-action: none; border-radius: 3px; }
.viewer canvas { display: block; width: 100%; height: 100%; }
.viewer.dragging { cursor: grabbing; }
.under { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 6px 16px; padding: 8px 0; font-size: 14px; }
.layers { display: flex; flex-wrap: wrap; gap: 14px; }
.layers label { display: inline-flex; align-items: center; gap: 5px; cursor: pointer; }
.readout { font-family: var(--mono); font-size: 13px; color: var(--muted); }
.readout b { color: var(--text); font-weight: 500; }
.k { display: inline-block; width: 10px; height: 10px; border-radius: 50%; border: 2px solid; }
.k-matched { border-color: var(--matched); }
.k-dets { border-color: var(--dets); }
.k-grid { border-color: var(--grid); border-radius: 0; }
.k-names { border-color: #d4b106; }
.k-foot { border-color: var(--foot); border-radius: 0; margin-left: 10px; }
.k-cam { border-color: var(--cam); margin-left: 14px; }
.popup { position: absolute; max-width: 270px; padding: 8px 10px; font-size: 13px; color: #eee;
  background: rgba(20, 20, 20, .92); border-radius: 3px; pointer-events: none; }

aside h2 { margin-top: 2px; }
.kv { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.kv th { text-align: left; font-weight: 400; color: var(--muted); padding: 6px 12px 6px 0; vertical-align: top; white-space: nowrap; }
.kv td { font-family: var(--mono); font-size: 13.5px; padding: 6px 0; text-align: right; }
.kv tr { border-bottom: 1px solid var(--line); }
.kv tr.main td { font-size: 16px; font-weight: 500; }
.kv tr.gap th, .kv tr.gap td { padding-top: 16px; }
.near { font-size: 14.5px; margin: 14px 0 6px; }
.note { font-size: 13.5px; color: var(--muted); }

.lower { display: grid; grid-template-columns: minmax(0, 1fr) 330px; gap: 28px; margin-top: 36px; align-items: start; }
.panel-head { display: flex; justify-content: space-between; align-items: baseline; font-size: 14.5px; }
.globe { position: relative; height: 460px; background: #050505; border-radius: 3px; overflow: hidden; }
.globe canvas { display: block; }
.globe-msg { position: absolute; inset: 0; display: grid; place-items: center; color: #888; margin: 0; }
.caption { font-size: 13.5px; color: var(--muted); margin: 6px 0 0; }
.names { list-style: none; margin: 0; padding: 0; max-height: 460px; overflow: auto; font-size: 14.5px; border-top: 1px solid var(--line); }
.names li { display: flex; justify-content: space-between; gap: 10px; padding: 6px 2px; border-bottom: 1px solid var(--line); }
.names li[data-i] { cursor: pointer; }
.names li[data-i]:hover { background: var(--field); }
.names .s { font-family: var(--mono); font-size: 13px; color: var(--muted); white-space: nowrap; }

/* failure */
.fail { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 32px; padding: 40px 0; }
.fail ul { padding-left: 20px; color: var(--muted); }
.fail li { margin-bottom: 6px; }
.fail figure { margin: 0; }
#fail-canvas { width: 100%; background: #000; border-radius: 3px; }
figcaption { font-size: 13.5px; color: var(--muted); margin-top: 6px; }
.btn { font: inherit; font-size: 15px; padding: 8px 14px; border: 1px solid var(--text); background: var(--text); color: var(--bg);
  border-radius: 4px; cursor: pointer; margin-right: 12px; }

.foot { max-width: 1180px; margin: 0 auto; padding: 20px 24px 40px; border-top: 1px solid var(--line);
  color: var(--muted); font-size: 13.5px; }

/* ---------------------------------------------------------- how it works page */
.doc { max-width: 760px; margin: 0 auto; padding-top: 48px; }
.doc h1 { margin-bottom: 8px; }
.doc h2 { font-size: 24px; margin: 48px 0 12px; padding-top: 8px; }
.doc h3 { font-size: 18px; margin: 28px 0 8px; }
.doc p, .doc li { font-size: 16.5px; }
.doc figure { margin: 24px 0; }
.doc figure svg { width: 100%; height: auto; display: block; }
.doc figcaption { font-size: 14px; }
.doc table { width: 100%; border-collapse: collapse; font-size: 15px; margin: 12px 0; }
.doc th, .doc td { text-align: left; padding: 7px 10px 7px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
.doc th { font-weight: 600; }
.doc td.n { font-family: var(--mono); font-size: 14px; }
.doc pre { background: var(--field); border: 1px solid var(--line); border-radius: 4px; padding: 12px 14px; overflow-x: auto; font-size: 13.5px; }
.doc .toc { font-size: 15px; columns: 2; padding-left: 20px; margin: 20px 0 0; }
.svg-text { fill: var(--text); font-family: var(--sans); font-size: 13px; }
.svg-muted { fill: var(--muted); font-family: var(--sans); font-size: 12px; }
.svg-line { stroke: var(--text); fill: none; }
.svg-box { stroke: var(--line); fill: var(--field); }

@media (max-width: 900px) {
  .result, .lower, .fail { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 600px) {
  main, .top, .foot { padding-left: 16px; padding-right: 16px; }
  #view-start { padding-top: 32px; }
  .examples { grid-template-columns: 1fr 1fr; }
  .opt { grid-template-columns: 1fr; }
  .viewer { height: 56vh; }
  .globe { height: 340px; }
  .doc .toc { columns: 1; }
}
.doc .katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }
.doc table { display: block; overflow-x: auto; }
.flow { list-style: none; padding: 0; margin: 24px 0; display: flex; gap: 22px; flex-wrap: wrap; counter-reset: none; }
.flow li { position: relative; flex: 1 1 120px; border: 1px solid var(--line); background: var(--field); border-radius: 4px;
  padding: 10px 12px; font-size: 15px; }
.flow li b { display: block; font-weight: 600; }
.flow li span { color: var(--muted); font-size: 13.5px; }
.flow li:not(:last-child)::after { content: "→"; position: absolute; right: -17px; top: 50%; transform: translateY(-50%); color: var(--muted); }
@media (max-width: 600px) {
  .flow { flex-direction: column; gap: 18px; }
  .flow li { flex: none; }
  .flow li:not(:last-child)::after { content: "↓"; right: auto; left: 50%; top: auto; bottom: -19px; transform: none; }
}