:root {
  color-scheme: light;
  --surface-0: #f7f7f5;
  --surface-1: #fcfcfb;
  --border: #dddcd7;
  --grid: #ecebe7;
  --text-primary: #0b0b0b;
  --text-secondary: #52514e;
  --text-muted: #6f6e69;
  --accent: #2a78d6;
  --series-1: #2a78d6;
  --marked: #e34948;
  --error: #b42323;
  --node-edge: #c9c8c2;
  /* Sequential blue ramp, light → dark (probability 0 → 1). */
  --seq-0: #e6effa;
  --seq-1: #104281;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --surface-0: #121211;
    --surface-1: #1a1a19;
    --border: #3a3a37;
    --grid: #2a2a28;
    --text-primary: #f0efec;
    --text-secondary: #c3c2b7;
    --text-muted: #9a998f;
    --accent: #6da7ec;
    --series-1: #3987e5;
    --marked: #e66767;
    --error: #f08080;
    --node-edge: #4a4a46;
    --seq-0: #22303f;
    --seq-1: #9ec5f4;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --surface-0: #121211;
  --surface-1: #1a1a19;
  --border: #3a3a37;
  --grid: #2a2a28;
  --text-primary: #f0efec;
  --text-secondary: #c3c2b7;
  --text-muted: #9a998f;
  --accent: #6da7ec;
  --series-1: #3987e5;
  --marked: #e66767;
  --error: #f08080;
  --node-edge: #4a4a46;
  --seq-0: #22303f;
  --seq-1: #9ec5f4;
}

* { box-sizing: border-box; }
body {
  margin: 0 auto;
  max-width: 1100px;
  padding: 0 16px 32px;
  background: var(--surface-0);
  color: var(--text-primary);
  font: 15px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif;
}
a { color: var(--accent); }
h1 { font-size: 1.6rem; margin: 24px 0 4px; }
h2 { font-size: 1rem; margin: 16px 0 8px; color: var(--text-secondary); font-weight: 600; }
.lede { margin: 0 0 4px; }
.muted { color: var(--text-muted); }
nav { font-size: 0.9rem; }
code, pre, textarea { font-family: var(--mono); }

.tabs { display: flex; gap: 4px; margin: 20px 0 0; border-bottom: 1px solid var(--border); overflow-x: auto; }
.tabs button {
  border: 1px solid transparent; border-bottom: none; border-radius: 6px 6px 0 0;
  background: none; color: var(--text-secondary); padding: 8px 14px; font: inherit; cursor: pointer;
  white-space: nowrap;
}
.tabs button[aria-selected="true"] {
  background: var(--surface-1); border-color: var(--border); color: var(--text-primary);
  margin-bottom: -1px; font-weight: 600;
}
main section {
  background: var(--surface-1); border: 1px solid var(--border); border-top: none;
  border-radius: 0 0 8px 8px; padding: 12px 16px 20px;
}

.controls { display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: end; margin: 8px 0; }
.controls label { display: flex; flex-direction: column; font-size: 0.85rem; color: var(--text-secondary); }
.controls label.grow { flex: 1 1 240px; flex-direction: row; align-items: center; gap: 8px; }
.controls output { min-width: 3.5em; font-family: var(--mono); color: var(--text-primary); }
input, select, textarea, button {
  font: inherit; color: var(--text-primary); background: var(--surface-0);
  border: 1px solid var(--border); border-radius: 6px; padding: 5px 8px;
}
input[type="number"] { width: 7em; }
input[type="range"] { padding: 0; width: 100%; }
button { cursor: pointer; }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; padding: 6px 18px; }
button:disabled { opacity: 0.6; cursor: progress; }
textarea { width: 100%; font-size: 0.85rem; line-height: 1.45; resize: vertical; }
pre { background: var(--surface-0); border: 1px solid var(--border); border-radius: 6px; padding: 8px; overflow-x: auto; font-size: 0.8rem; }

.status { min-height: 1.5em; margin: 6px 0; color: var(--text-secondary); }
.status.error { color: var(--error); }
.info { margin: 4px 0; color: var(--text-secondary); }
.split { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 16px; align-items: start; }
@media (max-width: 760px) { .split { grid-template-columns: minmax(0, 1fr); } }

.chart { width: 100%; max-width: 640px; }
.chart svg { display: block; width: 100%; height: auto; overflow: visible; }
.chart text { fill: var(--text-muted); font-size: 11px; font-family: var(--mono); }
.chart .axis { stroke: var(--border); }
.chart .gridline { stroke: var(--grid); }
.chart .bar { fill: var(--series-1); }
.chart .hit { fill: transparent; }
.chart .hit:hover + .bar, .chart .bar.active { opacity: 0.8; }
.chart .line { fill: none; stroke: var(--series-1); stroke-width: 2; }
.chart .crosshair { stroke: var(--text-muted); stroke-dasharray: 3 3; }
.chart .marker { fill: var(--series-1); stroke: var(--surface-1); stroke-width: 2; }
.graph .edge { stroke: var(--node-edge); stroke-width: 1; }
.graph .node { stroke: var(--surface-1); stroke-width: 2; cursor: pointer; }
.graph .node.marked { stroke: var(--marked); stroke-width: 3; }
.graph .label { fill: var(--text-secondary); font-size: 10px; pointer-events: none; text-anchor: middle; dominant-baseline: central; }

details { margin: 8px 0; }
summary { cursor: pointer; color: var(--text-secondary); }
.table-wrap { max-height: 320px; overflow: auto; }
table { border-collapse: collapse; font-size: 0.85rem; font-family: var(--mono); }
th, td { padding: 2px 12px; text-align: right; border-bottom: 1px solid var(--grid); }
th { color: var(--text-secondary); font-weight: 600; }

.tooltip {
  position: fixed; pointer-events: none; z-index: 10; padding: 4px 8px; border-radius: 6px;
  background: var(--text-primary); color: var(--surface-1); font: 12px/1.4 var(--mono); white-space: pre;
}
footer { margin-top: 24px; font-size: 0.85rem; }