:root {
  --bg: #ffffff;
  --surface: #f5f6f8;
  --text: #1f2328;
  --muted: #59636e;
  --border: #d1d9e0;
  --accent: #0969da;
  --error: #cf222e;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --surface: #161b22;
    --text: #e6edf3;
    --muted: #9198a1;
    --border: #3d444d;
    --accent: #4493f8;
    --error: #f85149;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0 auto;
  max-width: 1200px;
  padding: 24px 16px;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif;
}

a { color: var(--accent); }
h1 { margin: 0 0 4px; font-size: 1.6rem; }
header p, .examples, footer { color: var(--muted); }

label { display: block; margin-bottom: 4px; font-weight: 600; }
.row, .toolbar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.toolbar label { margin: 0; }

input, select, button {
  font: inherit;
  color: inherit;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 10px;
}
input { flex: 1 1 300px; min-width: 0; }
button { cursor: pointer; }
button[type="submit"] { background: var(--accent); border-color: var(--accent); color: #fff; }
button:disabled { opacity: 0.6; cursor: default; }

.examples a { margin-right: 12px; }
#status { min-height: 1.5em; }
#status.error { color: var(--error); white-space: pre-wrap; }

#diagram {
  margin: 12px 0;
  padding: 12px;
  overflow-x: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
}
#diagram svg { display: block; margin: 0 auto; }
#diagram.fit svg { max-width: 100%; height: auto; }
#diagram .node:has(> title) { cursor: help; }
.toolbar .check { display: flex; gap: 4px; align-items: center; font-weight: normal; }
.check input { flex: none; }

#details { display: grid; grid-template-columns: max-content 1fr; gap: 4px 16px; }
#details dt { font-weight: 600; }
#details dd { margin: 0; overflow-wrap: anywhere; }

footer { margin-top: 32px; font-size: 0.9em; }

@media (max-width: 600px) {
  #details { grid-template-columns: 1fr; }
  #details dd { margin-bottom: 8px; }
}