:root {
  --bg-green: #1e8e3e;
  --board-green: #2fa84f;
  --snake-blue: #0b57d0;
  --snake-head-blue: #2c7df0;
  --food-red: #d93025;
  --text: #f5fff7;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  background: radial-gradient(circle at top, #3bb35d 0%, var(--bg-green) 65%);
  color: var(--text);
  font-family: "Trebuchet MS", "Segoe UI", sans-serif;
}

.app {
  width: min(92vw, 540px);
  text-align: center;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(1.4rem, 2.4vw, 2rem);
}

.hud {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
  font-size: 1.05rem;
}

#restart {
  border: 0;
  border-radius: 10px;
  padding: 8px 12px;
  font-weight: 700;
  cursor: pointer;
  background: #ffffff;
  color: #1f3a22;
}

#game {
  width: min(92vw, 480px);
  height: min(92vw, 480px);
  background: var(--board-green);
  border: 4px solid #165f2d;
  border-radius: 10px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.2);
}

.help {
  margin-top: 10px;
  font-size: 0.95rem;
  opacity: 0.95;
}