:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --fg: #1c2024;
  --muted: #646b75;
  --border: #dfe3e8;
  --grid: rgba(0, 0, 0, 0.07);
  --accent: #2563eb;
  --accent-fg: #ffffff;
  --ok: #15803d;
  --bad: #b91c1c;
  --warn-bg: #fff7ed;
  --warn-border: #fdba74;
  --tip-shade: rgba(120, 120, 120, 0.1);
  --canvas-bg: #2a2e35;
  --radius: 8px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121417;
    --surface: #1b1e23;
    --fg: #e6e8eb;
    --muted: #99a1ab;
    --border: #2d3239;
    --grid: rgba(255, 255, 255, 0.08);
    --accent: #3b82f6;
    --ok: #4ade80;
    --bad: #f87171;
    --warn-bg: #2a1f12;
    --warn-border: #9a5b13;
    --tip-shade: rgba(160, 160, 160, 0.1);
    --canvas-bg: #0d0f12;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--bg);
  color: var(--fg);
  font: 14px/1.45 system-ui, -apple-system, "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
}
h1, h2, h3 { margin: 0; line-height: 1.2; }
h1 { font-size: 26px; }
h2 { font-size: 15px; }
h3 { font-size: 12px; font-weight: 600; color: var(--muted); text-transform: uppercase; letter-spacing: 0.04em; }
.muted { color: var(--muted); }
small { display: block; color: var(--muted); font-size: 12px; margin-top: 3px; }

button {
  font: inherit;
  color: var(--fg);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 5px 11px;
  cursor: pointer;
}
button:hover:not(:disabled) { border-color: var(--muted); }
button:disabled { opacity: 0.45; cursor: default; }
button.primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
button.ghost { border-color: transparent; background: none; color: var(--muted); }
button.on { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

input, select {
  font: inherit;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 8px;
  width: 100%;
  margin-top: 4px;
}
label { display: block; font-weight: 500; }
label.check { display: flex; gap: 8px; align-items: center; }
label.check input { width: auto; margin: 0; }
fieldset { border: 0; padding: 0; margin: 0; display: grid; gap: 10px; }

.row { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.stack { display: grid; gap: 6px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); }

/* top bar */
.topbar {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 10px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.brand { font-weight: 700; font-size: 16px; }
.steps { display: flex; gap: 4px; }
.steps button { border: 0; background: none; color: var(--muted); display: flex; gap: 7px; align-items: center; }
.steps button span {
  display: inline-grid; place-items: center;
  width: 20px; height: 20px; border-radius: 50%;
  border: 1px solid currentColor; font-size: 11px;
}
.steps button.current { color: var(--fg); font-weight: 600; }
.steps button.current span { background: var(--accent); border-color: var(--accent); color: var(--accent-fg); }
.steps button.done span { background: var(--ok); border-color: var(--ok); color: #fff; }
.project-name { margin-left: auto; color: var(--muted); }

main { flex: 1; min-height: 0; display: flex; }
.screen { display: none; flex: 1; min-width: 0; }
.screen.active { display: flex; }

/* setup */
[data-screen="setup"] { overflow: auto; justify-content: center; }
.setup { max-width: 560px; padding: 48px 20px; display: grid; gap: 18px; align-content: start; }
.lead { color: var(--muted); margin: 0; font-size: 15px; }
.form { padding: 20px; display: grid; gap: 16px; }
.secondary-actions button { font-size: 13px; }
.project-list { list-style: none; margin: 0; padding: 0; }
.project-list li {
  display: grid; grid-template-columns: 64px 1fr auto auto; gap: 12px; align-items: center;
  padding: 10px 12px; border-top: 1px solid var(--border);
}
.project-list li:first-child { border-top: 0; }
.project-list li.current { box-shadow: inset 3px 0 var(--accent); }
.project-list .thumb { width: 64px; height: 40px; border-radius: 4px; background: var(--canvas-bg) center / cover; }
.project-list .name { font-weight: 600; }
.project-list .meta { font-size: 12px; }

/* digitise */
.digitize { flex-direction: column; }
.toolbar {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: center;
  padding: 8px 12px; background: var(--surface); border-bottom: 1px solid var(--border);
}
.group { display: flex; gap: 4px; }
.segmented { gap: 0; }
.segmented button { border-radius: 0; margin-left: -1px; }
.segmented button:first-child { border-radius: 6px 0 0 6px; margin-left: 0; }
.segmented button:last-child { border-radius: 0 6px 6px 0; }
.segmented button.side-back.on { background: #2563eb; border-color: #2563eb; }
.segmented button.side-belly.on { background: #dc2626; border-color: #dc2626; }
.help { position: relative; margin-left: auto; }
.help summary { cursor: pointer; color: var(--muted); list-style: none; padding: 5px 8px; }
.help dl {
  position: absolute; right: 0; top: 30px; z-index: 5; width: 420px;
  display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; margin: 0;
  padding: 14px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.18); font-size: 13px;
}
.help dt { font-weight: 600; white-space: nowrap; }
.help dd { margin: 0; color: var(--muted); }
.canvas-wrap { position: relative; flex: 1; min-height: 0; overflow: hidden; background: var(--canvas-bg); }
.canvas-wrap canvas { position: absolute; inset: 0; display: block; touch-action: none; --canvas-bg: inherit; }
.canvas-wrap.dragover { outline: 3px dashed var(--accent); outline-offset: -8px; }
.empty {
  position: absolute; inset: 0; display: grid; place-content: center; justify-items: center;
  gap: 10px; color: #d6dae0; text-align: center; padding: 20px;
}
.empty h2 { font-size: 22px; color: #fff; }
.empty p { margin: 0; }
.empty .hint { max-width: 460px; color: #a3aab4; font-size: 13px; }
.statusbar {
  display: flex; align-items: center; gap: 16px; padding: 8px 12px;
  background: var(--surface); border-top: 1px solid var(--border);
}
.statusbar .spacer { flex: 1; }
.validity-ok { color: var(--ok); }
.validity-bad { color: var(--bad); }

/* results */
.results { overflow: auto; align-items: flex-start; gap: 16px; padding: 16px; }
.settings { position: sticky; top: 0; width: 260px; flex: none; padding: 16px; display: grid; gap: 14px; }
#settings-form { display: grid; gap: 12px; }
.report { flex: 1; min-width: 0; display: grid; gap: 16px; }
.cards { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; }
.metric { padding: 14px; }
.metric .value { font-size: 26px; font-weight: 650; margin: 6px 0 4px; font-variant-numeric: tabular-nums; }
.metric .detail { color: var(--muted); font-size: 12px; }
.metric.warn { background: var(--warn-bg); border-color: var(--warn-border); }
.panel { padding: 14px 16px; display: grid; gap: 12px; }
.panel-head { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.panel-head .muted { font-size: 12px; }
.bow-wrap { width: 100%; }
.bow-wrap canvas { display: block; }
.heatmap-legend { display: grid; grid-template-columns: auto minmax(120px, 360px) auto 1fr; gap: 8px; align-items: center; font-size: 12px; }
.heatmap-legend .bar { height: 10px; border-radius: 5px; }
.heatmap-legend .caption { grid-column: 1 / -1; margin: 0; }
.charts { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.charts h3 { margin-bottom: 4px; }
.fineprint { font-size: 12px; margin: 0; }
.report.stale > :not(.error) { display: none; }
.error { padding: 14px; border-color: var(--bad); color: var(--bad); }

.uplot { font-family: inherit; }
.u-legend { font-size: 12px; color: var(--fg); }
.u-legend .u-marker { width: 10px; height: 3px; }

.toast {
  position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%);
  background: var(--fg); color: var(--bg); padding: 8px 14px; border-radius: 6px; z-index: 20;
}