:root {
  --bg: #0b1220;
  --panel: #111a2e;
  --panel-2: #16213a;
  --border: rgba(148, 163, 184, 0.16);
  --text: #f8fafc;
  --muted: #94a3b8;
  --primary: #7c3aed;
  --primary-hover: #8b5cf6;
  --cyan: #22d3ee;
  --green: #34d399;
  --pink: #f472b6;
  --bar: #334155;
}

* { box-sizing: border-box; }

html { min-width: 320px; background: var(--bg); }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(124, 58, 237, 0.12), transparent 32rem),
    radial-gradient(circle at top right, rgba(34, 211, 238, 0.08), transparent 28rem),
    var(--bg);
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button, input, select { font: inherit; }
button, select, input { -webkit-tap-highlight-color: transparent; }

.site-header,
.app-shell,
.site-footer {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  padding: 28px 0 22px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.brand { display: flex; align-items: center; gap: 14px; }
.brand-mark {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), #a855f7);
  color: white;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.04em;
  box-shadow: 0 10px 30px rgba(124, 58, 237, 0.25);
}

.brand h1, .brand p, .visualizer-heading h2, .eyebrow { margin: 0; }
.brand h1 { font-size: clamp(1.1rem, 2vw, 1.35rem); line-height: 1.2; }
.brand p { margin-top: 4px; color: var(--muted); font-size: 0.78rem; }

.header-meta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 0.78rem;
}
.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0 4px rgba(52, 211, 153, 0.08);
}
.header-meta.is-active .status-dot {
  background: var(--cyan);
  animation: pulse 1.1s ease-in-out infinite;
}

.app-shell { padding-bottom: 30px; }
.control-panel, .visualizer-card, .info-card {
  border: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(17, 26, 46, 0.98), rgba(14, 22, 39, 0.98));
  border-radius: 20px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.18);
}
.control-panel { padding: 20px; }

.controls-grid {
  display: grid;
  grid-template-columns: minmax(170px, 1.1fr) minmax(180px, 1fr) minmax(180px, 1fr) auto;
  gap: 16px;
  align-items: end;
}
.control-group { display: grid; gap: 8px; }
.control-group label { color: var(--muted); font-size: 0.76rem; font-weight: 600; }
.control-input {
  width: 100%;
  min-height: 42px;
  padding: 0 12px;
  color: var(--text);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  outline: none;
}
.control-input:focus {
  border-color: rgba(124, 58, 237, 0.7);
  box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.12);
}
.control-input:disabled, .range-input:disabled, button:disabled { cursor: not-allowed; opacity: 0.55; }
.range-input { width: 100%; accent-color: var(--primary); cursor: pointer; }

.control-actions { display: flex; gap: 10px; }
.btn {
  min-height: 42px;
  padding: 0 15px;
  border: 0;
  border-radius: 10px;
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 160ms ease, background 160ms ease, box-shadow 160ms ease;
}
.btn:hover:not(:disabled) { transform: translateY(-1px); }
.btn:active:not(:disabled) { transform: translateY(0); }
.btn-primary { color: white; background: var(--primary); box-shadow: 0 10px 22px rgba(124, 58, 237, 0.22); }
.btn-primary:hover:not(:disabled) { background: var(--primary-hover); }
.btn-secondary { color: var(--text); background: var(--panel-2); border: 1px solid var(--border); }

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  padding-top: 18px;
  margin-top: 18px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.72rem;
}
.legend span { display: inline-flex; align-items: center; gap: 6px; }
.legend-swatch { width: 8px; height: 8px; display: inline-block; border-radius: 50%; background: var(--bar); }
.legend-swatch.current { background: var(--cyan); }
.legend-swatch.min { background: var(--pink); }
.legend-swatch.done { background: var(--green); }

.visualizer-card { margin-top: 18px; padding: 20px; }
.visualizer-heading { display: flex; justify-content: space-between; align-items: flex-start; gap: 16px; margin-bottom: 18px; }
.eyebrow { color: var(--cyan); font-size: 0.66rem; font-weight: 800; letter-spacing: 0.12em; }
.visualizer-heading h2 { margin-top: 6px; font-size: clamp(1rem, 2.2vw, 1.25rem); }
.stats { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; justify-content: flex-end; }
.stats span { padding: 7px 10px; border: 1px solid var(--border); border-radius: 999px; color: var(--muted); font-size: 0.7rem; background: rgba(22, 33, 58, 0.72); }

.visualizer-stage {
  position: relative;
  min-height: 470px;
  padding: 18px 12px 12px 34px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 15px;
  background:
    linear-gradient(rgba(148, 163, 184, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.035) 1px, transparent 1px),
    #0d1629;
  background-size: 32px 32px;
}
.array { height: 430px; width: 100%; display: flex; align-items: flex-end; justify-content: center; gap: clamp(1px, 0.18vw, 3px); }
.cell {
  flex: 1 1 0;
  min-width: 2px;
  max-width: 22px;
  border-radius: 5px 5px 1px 1px;
  background: linear-gradient(180deg, #64748b, var(--bar));
  box-shadow: inset 0 1px rgba(255, 255, 255, 0.08);
  transition: height 100ms ease, background 120ms ease, transform 120ms ease;
}
.cell.current { background: linear-gradient(180deg, #67e8f9, var(--cyan)); transform: translateY(-2px); }
.cell.min { background: linear-gradient(180deg, #f9a8d4, var(--pink)); }
.cell.done { background: linear-gradient(180deg, #86efac, var(--green)); }

.axis-label { position: absolute; left: 10px; color: rgba(148, 163, 184, 0.55); font-size: 0.6rem; }
.axis-top { top: 10px; }
.axis-bottom { bottom: 10px; }
.empty-state { position: absolute; inset: 0; display: grid; place-items: center; color: var(--muted); font-size: 0.85rem; }

.info-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 18px; }
.info-card { padding: 17px 18px; }
.info-card span, .info-card strong { display: block; }
.info-card span { color: var(--muted); font-size: 0.68rem; margin-bottom: 7px; }
.info-card strong { font-size: 0.88rem; }
.info-card-wide { grid-column: span 4; }

.site-footer { padding: 0 0 28px; display: flex; justify-content: space-between; gap: 16px; color: var(--muted); font-size: 0.72rem; }
.footer-links { display: flex; gap: 14px; }
.footer-links a { color: var(--muted); text-decoration: none; }
.footer-links a:hover { color: var(--text); }

@keyframes pulse {
  0%, 100% { opacity: 0.45; transform: scale(0.9); }
  50% { opacity: 1; transform: scale(1.1); }
}

@media (max-width: 900px) {
  .controls-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .control-actions { grid-column: 1 / -1; }
  .control-actions .btn { flex: 1; }
  .info-grid { grid-template-columns: repeat(2, 1fr); }
  .info-card-wide { grid-column: span 2; }
}

@media (max-width: 640px) {
  .site-header, .app-shell, .site-footer { width: min(100% - 20px, 1180px); }
  .site-header { padding-top: 18px; }
  .header-meta { display: none; }
  .control-panel, .visualizer-card { padding: 14px; border-radius: 16px; }
  .controls-grid { grid-template-columns: 1fr; }
  .control-actions { grid-column: auto; }
  .visualizer-heading { flex-direction: column; }
  .stats { justify-content: flex-start; }
  .visualizer-stage { min-height: 360px; padding: 10px 6px 6px 26px; }
  .array { height: 320px; }
  .cell { max-width: 12px; border-radius: 3px 3px 1px 1px; }
  .info-grid { grid-template-columns: 1fr 1fr; }
  .info-card-wide { grid-column: span 2; }
  .site-footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}