/* Light, clean, and a bit playful */
:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-600: #1d4ed8;
  --danger: #ef4444;
  --ring: rgba(37, 99, 235, 0.25);
  --border: #e2e8f0;
  --grid: #e5e7eb;
  --alive: #0ea5e9;
  --alive-2: #22c55e;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, "Helvetica Neue", Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: radial-gradient(1200px 800px at 10% -20%, #ffffff, var(--bg));
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
}

.app-header {
  background: linear-gradient(180deg, #ffffff, #f7fafc00 60%);
  border-bottom: 1px solid var(--border);
}

.app-header .container {
  padding: 24px 16px 18px;
}

h1 {
  margin: 0;
  font-size: 28px;
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 4px 0 0 0;
  color: var(--muted);
}

main.container {
  padding-top: 18px;
  padding-bottom: 24px;
}

.panel {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 1px 1px rgba(16, 24, 40, 0.04), 0 4px 10px rgba(16, 24, 40, 0.05);
}

.controls {
  margin-bottom: 16px;
}

.row {
  display: flex;
  align-items: center;
}

.wrap {
  flex-wrap: wrap;
}

.gap {
  gap: 12px 20px;
}

.top {
  margin-top: 10px;
}

.group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.group label {
  font-size: 12px;
  color: var(--muted);
}

input[type="number"],
input[type="range"] {
  accent-color: var(--primary);
}

input[type="number"] {
  width: 110px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #fff;
  color: var(--text);
  outline: none;
}

input[type="number"]:focus {
  box-shadow: 0 0 0 4px var(--ring);
  border-color: var(--primary);
}

#speed {
  width: 220px;
}

.btn {
  padding: 10px 14px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  cursor: pointer;
  transition: transform 0.02s ease, box-shadow 0.2s ease, background 0.2s ease, border 0.2s ease;
}

.btn:hover {
  box-shadow: 0 2px 10px rgba(16, 24, 40, 0.08);
}

.btn:active {
  transform: translateY(1px);
}

.btn.primary {
  background: var(--primary);
  color: white;
  border-color: var(--primary-600);
}

.btn.primary:hover {
  background: var(--primary-600);
}

.btn.danger {
  background: #fff5f5;
  color: #b91c1c;
  border-color: #fecaca;
}

.pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 64px;
  padding: 6px 10px;
  background: #f1f5f9;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-variant-numeric: tabular-nums;
}

.spacer {
  flex: 1;
}

.canvas-panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.canvas-holder {
  display: inline-block;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 5px;
  overflow: hidden;
  box-shadow: inset 0 0 0 1px #eef2f7;
}

.hint {
  color: var(--muted);
  margin: 0;
  font-size: 12px;
}

.footer {
  color: var(--muted);
  padding-bottom: 36px;
  text-align: center;
}

/* Grid visuals */
.canvas-holder canvas {
  image-rendering: pixelated;
  display: block;
}

/* Responsive nits */
@media (max-width: 640px) {
  #speed {
    width: 160px;
  }
  .controls .row {
    flex-direction: column;
    align-items: stretch;
    gap: 10px 0;
  }
  .controls .group {
    width: 100%;
    flex-direction: row;
    align-items: center;
    gap: 8px;
  }
  .controls .group label {
    min-width: 80px;
    flex: 0 0 80px;
    margin-bottom: 0;
  }
  .controls button,
  .controls input[type="number"],
  .controls input[type="range"] {
    width: 100%;
    min-width: 0;
    box-sizing: border-box;
  }
  .controls .row.top {
    flex-direction: column;
    gap: 10px 0;
  }
  .panel {
    padding: 10px;
  }
}