:root {
  --bg: #081632;
  --panel: #0d2147;
  --grid: #183569;
  --text: #f5f8ff;
  --accent: #ffbf1f;
  --snake: #36d399;
  --head: #14b8a6;
  --food: #ff6b35;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, Segoe UI, system-ui, sans-serif;
  background: radial-gradient(circle at top, #113266 0%, var(--bg) 70%);
  color: var(--text);
  display: grid;
  place-items: center;
  padding: 1rem;
}

.app {
  width: min(92vw, 620px);
  background: color-mix(in srgb, var(--panel), black 10%);
  border: 1px solid color-mix(in srgb, var(--accent), transparent 50%);
  border-radius: 12px;
  padding: 1rem;
}

.brand {
  margin: 0;
  letter-spacing: 0.25rem;
  color: var(--accent);
  font-weight: 700;
}

.header h1 {
  margin: 0.2rem 0;
}

.subtitle {
  margin: 0;
  opacity: 0.85;
}

.hud {
  display: flex;
  justify-content: space-between;
  margin: 1rem 0;
}

.board {
  --grid-size: 16;
  display: grid;
  grid-template-columns: repeat(var(--grid-size), 1fr);
  background: #061022;
  border: 1px solid #244072;
  border-radius: 6px;
  overflow: hidden;
}

.cell {
  aspect-ratio: 1 / 1;
  border: 1px solid color-mix(in srgb, var(--grid), black 25%);
  background: #102241;
}

.cell.snake {
  background: var(--snake);
}

.cell.head {
  background: var(--head);
}

.cell.food {
  background: var(--food);
}

.controls {
  margin-top: 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.controls div {
  display: flex;
  gap: 0.5rem;
}

button {
  border: 1px solid #3c5f98;
  background: #163460;
  color: var(--text);
  border-radius: 6px;
  padding: 0.45rem 0.75rem;
  font: inherit;
  cursor: pointer;
}

button:hover {
  background: #1d3f70;
}

.actions {
  margin-top: 0.8rem;
}

.hint {
  margin: 0.8rem 0 0;
  font-size: 0.9rem;
  opacity: 0.8;
}