:root {
  --bg: #0b0f17;
  --panel: #121826;
  --panel-2: #182033;
  --border: #243049;
  --text: #e6edf7;
  --muted: #8b97ad;
  --accent: #6c8cff;
  --bar: #4f6bd8;
  --compare: #f5c542;
  --swap: #ff5d73;
  --pivot: #b67cff;
  --sorted: #2fd18b;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(1200px 600px at 10% -10%, #1a2340 0%, transparent 60%), var(--bg);
  color: var(--text);
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  display: flex;
  flex-direction: column;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding: 18px 28px;
  border-bottom: 1px solid var(--border);
  background: rgba(11, 15, 23, 0.7);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 5;
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand h1 { font-size: 1.2rem; margin: 0; letter-spacing: 0.2px; }

.logo { display: inline-flex; align-items: flex-end; gap: 3px; height: 24px; }
.logo i { width: 5px; border-radius: 2px; background: var(--accent); }
.logo i:nth-child(1) { height: 40%; }
.logo i:nth-child(2) { height: 70%; background: var(--compare); }
.logo i:nth-child(3) { height: 55%; background: var(--swap); }
.logo i:nth-child(4) { height: 100%; background: var(--sorted); }

.algo-pills { display: flex; flex-wrap: wrap; gap: 6px; }
.pill {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--muted);
  padding: 8px 14px;
  border-radius: 999px;
  cursor: pointer;
  font: inherit;
  font-size: 0.88rem;
  transition: all 0.15s;
}
.pill:hover { color: var(--text); border-color: var(--accent); }
.pill.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.pill:disabled { opacity: 0.5; cursor: not-allowed; }

.layout {
  flex: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 20px;
  padding: 20px 28px;
  align-items: start;
}

.stage-card, .card {
  background: linear-gradient(180deg, var(--panel) 0%, #0f1522 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 18px;
}
.control { display: flex; flex-direction: column; gap: 6px; min-width: 170px; flex: 1; }
.control label { font-size: 0.82rem; color: var(--muted); display: flex; justify-content: space-between; }
.control output { color: var(--text); font-weight: 600; }

input[type="range"] { width: 100%; accent-color: var(--accent); }

.buttons { display: flex; gap: 8px; }
.btn {
  font: inherit;
  font-size: 0.9rem;
  padding: 9px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: transform 0.08s, background 0.15s;
}
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; min-width: 88px; font-weight: 600; }
.btn.primary:hover { background: #5878f5; }
.btn.ghost { background: var(--panel-2); color: var(--text); }
.btn.ghost:hover { border-color: var(--accent); }
.btn.small { padding: 6px 10px; font-size: 0.8rem; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin: 16px 0;
}
.stat {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
}
.stat span { display: block; font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.8px; color: var(--muted); }
.stat strong { font-size: 1.35rem; font-variant-numeric: tabular-nums; }

.bars {
  height: 420px;
  display: flex;
  align-items: flex-end;
  gap: 2px;
  padding: 12px;
  background: #0a0e16;
  border: 1px solid var(--border);
  border-radius: 12px;
}
.bar {
  flex: 1;
  min-width: 2px;
  background: var(--bar);
  border-radius: 3px 3px 0 0;
  position: relative;
  transition: background 0.08s;
}
.bar.compare { background: var(--compare); }
.bar.swap { background: var(--swap); }
.bar.pivot { background: var(--pivot); }
.bar.sorted { background: var(--sorted); }
.bar .val {
  position: absolute;
  top: -18px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 10px;
  color: var(--muted);
}

.legend { list-style: none; display: flex; flex-wrap: wrap; gap: 16px; padding: 0; margin: 14px 0 0; color: var(--muted); font-size: 0.85rem; }
.legend li { display: flex; align-items: center; gap: 6px; }
.sw { width: 12px; height: 12px; border-radius: 3px; display: inline-block; }
.sw.default { background: var(--bar); }
.sw.compare { background: var(--compare); }
.sw.swap { background: var(--swap); }
.sw.pivot { background: var(--pivot); }
.sw.sorted { background: var(--sorted); }

.side { display: flex; flex-direction: column; gap: 20px; }
.card h2 { margin: 0 0 8px; font-size: 1.05rem; }
.info p { color: #c3cce0; font-size: 0.9rem; line-height: 1.5; }
.complexity { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.complexity th { text-align: left; color: var(--muted); font-weight: 500; padding: 6px 0; width: 45%; }
.complexity td { padding: 6px 0; font-family: "JetBrains Mono", Consolas, monospace; }
.complexity tr + tr { border-top: 1px solid var(--border); }
.badge { padding: 2px 8px; border-radius: 999px; font-size: 0.78rem; font-family: inherit; }
.badge.yes { background: rgba(47, 209, 139, 0.15); color: var(--sorted); }
.badge.no { background: rgba(255, 93, 115, 0.15); color: var(--swap); }
.use { font-size: 0.85rem !important; }

.compare-head { display: flex; align-items: center; justify-content: space-between; }
.hint { color: var(--muted); font-size: 0.8rem; margin: 4px 0 10px; }
.results { width: 100%; border-collapse: collapse; font-size: 0.82rem; }
.results th { text-align: left; color: var(--muted); font-weight: 500; padding: 6px 4px; border-bottom: 1px solid var(--border); }
.results td { padding: 6px 4px; font-variant-numeric: tabular-nums; border-bottom: 1px solid #1b2438; }
.results tr.best td:first-child::after { content: " ★"; color: var(--compare); }

.footer { text-align: center; color: var(--muted); font-size: 0.8rem; padding: 14px; border-top: 1px solid var(--border); }
kbd { background: var(--panel-2); border: 1px solid var(--border); border-radius: 4px; padding: 1px 5px; font-size: 0.75rem; }

@media (max-width: 980px) {
  .layout { grid-template-columns: 1fr; padding: 14px; }
  .topbar { padding: 14px; }
  .bars { height: 300px; }
}
@media (max-width: 560px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
  .buttons { width: 100%; }
  .buttons .btn { flex: 1; }
  .bar .val { display: none; }
}