:root {
  color-scheme: light dark;
  --bg: light-dark(#f5f2eb, #171815);
  --panel: light-dark(#fffdf8, #22231f);
  --ink: light-dark(#24231f, #f2efe5);
  --muted: light-dark(#66635b, #aaa79e);
  --line: light-dark(#d5d0c5, #44453f);
  --blue: light-dark(#1769aa, #63b3ed);
  --red: light-dark(#b33a3a, #ff7777);
  --green: light-dark(#357a38, #75c878);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.4 system-ui, sans-serif;
}

main {
  width: min(1120px, calc(100% - 28px));
  margin: 24px auto 48px;
}

h1 { margin: 0 0 16px; font-size: 24px; }
h2 { margin: 0 0 10px; font-size: 16px; }

.controls,
.navigator,
.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 2px;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
  align-items: end;
  padding: 14px;
}

label { display: inline-flex; gap: 7px; align-items: center; }
label.stack { display: grid; gap: 4px; }
label.stack > span:first-child { color: var(--muted); font-size: 12px; }

input,
select,
button {
  color: inherit;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 7px 9px;
  font: inherit;
}

input[type="checkbox"] { accent-color: var(--blue); }
input[type="text"] { width: 180px; font-family: ui-monospace, monospace; }
button { cursor: pointer; }
button:hover { border-color: var(--blue); }
button:disabled { opacity: .45; cursor: default; }
.jump-control { display: flex; gap: 4px; }

.navigator {
  margin-top: 12px;
  padding: 12px 14px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 12px;
  align-items: center;
}

.current { text-align: center; }

#permutation {
  font: 700 24px/1.2 ui-monospace, monospace;
  letter-spacing: 2px;
}

#position,
#properties {
  color: var(--muted);
  font-size: 13px;
}

#properties { margin-top: 3px; }

.viewer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, .72fr);
  gap: 12px;
  margin-top: 12px;
}

.panel { padding: 14px; overflow: auto; }

#diagram {
  display: block;
  width: 100%;
  min-width: 430px;
  height: auto;
}

table {
  border-collapse: collapse;
  margin: auto;
  font-family: ui-monospace, monospace;
}

th,
td {
  width: 30px;
  height: 30px;
  text-align: center;
  border: 1px solid var(--line);
}

th { color: var(--muted); font-weight: 500; }
td.allowed { color: var(--blue); font-weight: 700; }
td.cover { background: color-mix(in srgb, var(--blue) 14%, transparent); }
td.diagonal { color: var(--green); }

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 10px;
  color: var(--muted);
  font-size: 12px;
}

.swatch {
  display: inline-block;
  width: 11px;
  height: 11px;
  margin-right: 4px;
  vertical-align: -1px;
}

.swatch.dot { border-radius: 50%; background: var(--blue); }
.swatch.arrow { height: 2px; background: var(--red); vertical-align: 3px; }
.swatch.cover {
  background: color-mix(in srgb, var(--blue) 25%, transparent);
  border: 1px solid var(--blue);
}

#message { min-height: 20px; margin-top: 10px; color: var(--red); }

@media (max-width: 800px) {
  .viewer-grid { grid-template-columns: 1fr; }
}