:root {
  --sn-bg: #020617;
  --sn-surface: #020617;
  --sn-border: #1e293b;
  --sn-snake: #22c55e;
  --sn-snake-head: #4ade80;
  --sn-food: #fb923c;
  --sn-grid: rgba(30, 64, 175, 0.25);
  --sn-text: #e5e7eb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: radial-gradient(circle at top, #1f2937, #020617 60%);
  color: var(--sn-text);
}

.sn-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid rgba(148, 163, 184, 0.3);
  background: linear-gradient(90deg, rgba(34, 197, 94, 0.16), rgba(56, 189, 248, 0.16));
  backdrop-filter: blur(10px);
}

.sn-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--sn-text);
}

.sn-title {
  margin: 0.5rem 0 0;
  font-size: 1.8rem;
}

.sn-subtitle {
  margin: 0.25rem 0 0;
  font-size: 0.95rem;
  color: #cbd5f5;
}

.sn-main {
  max-width: 960px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 2.5rem;
}

.sn-top {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
}

.sn-score-block {
  min-width: 90px;
  padding: 0.6rem 0.9rem;
  border-radius: 0.8rem;
  background: rgba(15, 23, 42, 0.9);
  border: 1px solid rgba(148, 163, 184, 0.4);
  text-align: center;
}

.sn-score-label {
  font-size: 0.8rem;
  color: #9ca3af;
}

.sn-score-value {
  font-size: 1.4rem;
  font-weight: 700;
}

.sn-btn {
  padding: 0.6rem 1.1rem;
  border-radius: 999px;
  border: none;
  background: linear-gradient(135deg, #22c55e, #14b8a6);
  color: #022c22;
  font-weight: 600;
  cursor: pointer;
}

.sn-board-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

#board {
  background: radial-gradient(circle at top, rgba(34, 197, 94, 0.18), #020617 70%);
  border-radius: 1.1rem;
  border: 2px solid var(--sn-border);
  box-shadow: 0 26px 60px rgba(15, 23, 42, 0.9);
}

.sn-mobile-controls {
  margin-top: 0.75rem;
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
}

.sn-mobile-row {
  display: flex;
  gap: 0.35rem;
}

.sn-mobile-controls button {
  border: none;
  border-radius: 0.9rem;
  padding: 0.7rem 1.2rem;
  background: rgba(15, 23, 42, 0.95);
  color: #e5e7eb;
  font-size: 1.5rem;
}

.sn-status {
  min-height: 2rem;
  font-size: 0.95rem;
  text-align: center;
  color: #e5e7eb;
}

.sn-help {
  margin-top: 2rem;
  padding: 1.25rem 1rem;
  border-radius: 1rem;
  background: rgba(15, 23, 42, 0.9);
  border: 1px solid rgba(148, 163, 184, 0.4);
}

.sn-help h2 {
  margin-top: 0;
  margin-bottom: 0.75rem;
}

.sn-help ul {
  margin: 0;
  padding-left: 1.2rem;
}

.sn-help li {
  margin-bottom: 0.35rem;
}

@media (max-width: 640px) {
  .sn-main {
    padding-inline: 0.75rem;
  }

  #board {
    width: 320px;
    height: 320px;
  }

  .sn-mobile-controls {
    display: flex;
  }
}