/* Big O Visualizer — Styles */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --primary: #06B6D4; --primary-light: #22D3EE;
  --accent: #F59E0B; --accent-glow: rgba(245,158,11,0.15);
  --success: #10B981; --danger: #EF4444; --warning: #F59E0B;
  --bg: #0A0F14; --bg-card: rgba(255,255,255,0.04);
  --bg-glass: rgba(255,255,255,0.06); --border: rgba(255,255,255,0.08);
  --text: #E8E8E8; --text-dim: #9CA3AF; --text-muted: #6B7280;
  --radius: 12px; --radius-sm: 8px;
  --font: 'Inter', system-ui, sans-serif; --mono: 'JetBrains Mono', monospace;
  --shadow: 0 4px 24px rgba(0,0,0,0.3); --transition: 250ms ease;
}
html { font-size: 16px; } body { font-family: var(--font); background: var(--bg); color: var(--text); line-height: 1.6; min-height: 100vh; -webkit-font-smoothing: antialiased; }

.header { position: sticky; top: 0; z-index: 100; background: rgba(10,15,20,0.85); backdrop-filter: blur(20px); border-bottom: 1px solid var(--border); }
.header__inner { max-width: 960px; margin: 0 auto; padding: 0.75rem 1.5rem; display: flex; align-items: center; justify-content: space-between; }
.header__brand { display: flex; align-items: center; gap: 0.6rem; }
.header__icon { font-size: 1.3rem; } .header__title { font-size: 1.15rem; font-weight: 700; }
.header__actions { display: flex; gap: 0.5rem; }

.btn { display: inline-flex; align-items: center; gap: 0.4rem; border: none; cursor: pointer; font-family: var(--font); font-size: 0.85rem; font-weight: 500; border-radius: var(--radius-sm); transition: all var(--transition); }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn--ghost { background: var(--bg-glass); color: var(--text-dim); padding: 0.5rem 0.85rem; border: 1px solid var(--border); }
.btn--ghost:hover { background: rgba(255,255,255,0.1); color: var(--text); }

.main { max-width: 960px; margin: 0 auto; padding: 1.25rem 1.5rem 3rem; }

.controls { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem; margin-bottom: 1rem; }
.controls__row { display: flex; gap: 1.5rem; align-items: flex-start; flex-wrap: wrap; }
.control-group { display: flex; flex-direction: column; gap: 0.3rem; }
.control-label { font-size: 0.72rem; font-weight: 600; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.04em; }
.control-value { font-family: var(--mono); font-size: 0.85rem; color: var(--primary-light); font-weight: 600; }
.slider { -webkit-appearance: none; appearance: none; width: 200px; height: 6px; border-radius: 3px; background: rgba(255,255,255,0.1); outline: none; }
.slider::-webkit-slider-thumb { -webkit-appearance: none; appearance: none; width: 18px; height: 18px; border-radius: 50%; background: var(--primary); cursor: pointer; }
.control-group--checks { display: flex; gap: 0.5rem; flex-wrap: wrap; flex: 1; align-items: center; padding-top: 0.15rem; }

.check-item { display: flex; align-items: center; gap: 0.3rem; cursor: pointer; }
.check-item input { accent-color: var(--primary); cursor: pointer; }
.check-item label { font-size: 0.8rem; cursor: pointer; font-family: var(--mono); }

.chart-section { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem; margin-bottom: 1rem; }
#chart-canvas { width: 100%; height: auto; display: block; }
.chart-legend { display: flex; gap: 1rem; flex-wrap: wrap; margin-top: 0.75rem; }
.legend-item { display: flex; align-items: center; gap: 0.35rem; font-size: 0.78rem; font-family: var(--mono); }
.legend-dot { width: 10px; height: 10px; border-radius: 50%; }

.section-title { font-size: 0.9rem; font-weight: 600; margin-bottom: 0.75rem; }

.perf-section { margin-bottom: 1rem; }
.perf-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); gap: 0.5rem; }
.perf-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 0.6rem 0.8rem; text-align: center; }
.perf-card__name { font-size: 0.72rem; font-weight: 600; color: var(--text-dim); font-family: var(--mono); }
.perf-card__value { font-size: 1.15rem; font-weight: 700; font-family: var(--mono); margin-top: 0.15rem; }

.code-section { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem; }
.code-tabs { display: flex; gap: 0.35rem; flex-wrap: wrap; margin-bottom: 0.75rem; }
.code-tab { font-size: 0.78rem; padding: 0.3rem 0.65rem; border-radius: var(--radius-sm); background: var(--bg-glass); color: var(--text-dim); border: 1px solid var(--border); cursor: pointer; font-family: var(--mono); transition: all var(--transition); }
.code-tab:hover { background: rgba(255,255,255,0.1); }
.code-tab--active { background: var(--primary); color: #fff; border-color: var(--primary); }
.code-block { background: rgba(0,0,0,0.4); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 0.85rem; overflow-x: auto; }
.code-block code { font-family: var(--mono); font-size: 0.82rem; color: var(--text); line-height: 1.6; white-space: pre; }

.toast { position: fixed; bottom: 1.5rem; left: 50%; transform: translateX(-50%); background: var(--primary); color: #fff; padding: 0.6rem 1.25rem; border-radius: var(--radius); font-size: 0.85rem; font-weight: 500; box-shadow: var(--shadow); z-index: 500; animation: toastIn 300ms ease; }
.toast[hidden] { display: none; }
@keyframes toastIn { from { opacity: 0; transform: translateX(-50%) translateY(10px); } to { opacity: 1; transform: translateX(-50%) translateY(0); } }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
@media (max-width: 600px) { .main { padding: 1rem; } .slider { width: 140px; } }