:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --ink: #e2e8f0;
  --accent: #38bdf8;
  --border: #334155;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Yu Gothic", sans-serif;
  min-height: 100vh;
}

.app {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px;
}

h1 {
  font-size: 20px;
  margin: 0 0 12px;
  letter-spacing: 0.08em;
  color: var(--accent);
}

h2 {
  font-size: 12px;
  margin: 0 0 6px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #94a3b8;
}

.layout {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

canvas#board {
  background: #020617;
  border: 2px solid var(--border);
  border-radius: 6px;
  image-rendering: pixelated;
  touch-action: none;
}

canvas#next {
  background: #020617;
  border: 1px solid var(--border);
  border-radius: 4px;
}

.panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 14px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px;
  min-width: 180px;
}

.score, .chain {
  font-variant-numeric: tabular-nums;
  font-size: 24px;
  font-weight: 700;
}

.controls ul {
  list-style: none;
  padding: 0;
  margin: 0 0 8px;
  font-size: 12px;
  line-height: 1.6;
  color: #cbd5e1;
}

button {
  background: var(--accent);
  color: #0f172a;
  border: 0;
  border-radius: 4px;
  padding: 6px 10px;
  font-weight: 700;
  cursor: pointer;
}
button:hover { filter: brightness(1.1); }

.status {
  margin-top: 12px;
  min-height: 1.4em;
  color: #fbbf24;
  font-weight: 700;
}

@media (max-width: 640px) {
  .layout { flex-direction: column; align-items: center; }
  .panel { width: 100%; }
  canvas#board {
    max-width: 100%;
    height: auto;
  }
}