@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;700&display=swap');

:root {
  --bg-main: #151922;
  --bg-card: #23283a;
  --bg-board: #181f2a;
  --accent: #2563eb;
  --accent-light: #60a5fa;
  --snake-head: #2563eb;
  --snake-body: #60a5fa;
  --food: #f43f5e;
  --text-main: #f3f6fa;
  --text-light: #fff;
  --shadow: 0 4px 24px rgba(24,31,42,0.18);
  --radius: 16px;
  --font-main: 'Inter', Arial, sans-serif;
}

html, body {
  height: 100%;
  width: 100%;
  background: var(--bg-main);
  font-family: var(--font-main);
}

body {
  min-height: 100vh;
  min-width: 100vw;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  gap: 2rem;
  overflow: hidden;
}

.header {
  margin-top: 2.5rem;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 1px;
  text-align: center;
  user-select: none;
}

.instructions {
  position: absolute;
  left: 4%;
  top: 4%;
  background: var(--bg-card);
  color: var(--text-main);
  border-radius: var(--radius);
  padding: 1.2rem 2rem;
  font-size: 1rem;
  font-weight: 500;
  box-shadow: var(--shadow);
  border: none;
  z-index: 10;
  max-width: 300px;
  line-height: 1.6;
  opacity: 0.97;
}
.instructions strong {
  color: var(--accent);
}

.leader-board {
  position: absolute;
  right: 4%;
  top: 4%;
  background: var(--bg-card);
  color: var(--text-main);
  border-radius: var(--radius);
  padding: 1.2rem 2rem;
  font-size: 1.2rem;
  font-weight: 700;
  box-shadow: var(--shadow);
  border: none;
  min-width: 180px;
  text-align: left;
  letter-spacing: 0.5px;
}
.leader-board span {
  color: var(--accent);
  margin-left: 8px;
  font-weight: 700;
}

.container {
  height: 70vh;
  width: 70vh;
  max-width: 90vw;
  max-height: 90vw;
  background: var(--bg-board);
  border-radius: var(--radius);
  display: grid;
  grid-template-columns: repeat(20, 1fr);
  grid-template-rows: repeat(20, 1fr);
  padding: 10px;
  gap: 2px;
  box-shadow: var(--shadow);
  position: relative;
  border: none;
}

.container #head {
  height: 100%;
  width: 100%;
  background: var(--snake-head);
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(37,99,235,0.15);
  border: none;
  transition: all 0.1s cubic-bezier(.4,2,.6,1);
  transform-origin: center;
}

.container .body {
  height: 90%;
  width: 90%;
  border-radius: 6px;
  background: var(--snake-body);
  box-shadow: 0 1px 4px rgba(96,165,250,0.10);
  border: none;
  transition: all 0.1s cubic-bezier(.4,2,.6,1);
  transform-origin: center;
}

.container .food {
  height: 100%;
  width: 100%;
  border-radius: 50%;
  background: var(--food);
  box-shadow: 0 0 8px rgba(244,63,94,0.18);
  border: none;
  animation: foodPulse 1s infinite ease-in-out;
}

@keyframes foodPulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.12); }
  100% { transform: scale(1); }
}

.game-over {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--bg-card);
  padding: 2.5rem 3.5rem;
  border-radius: var(--radius);
  text-align: center;
  color: var(--text-main);
  z-index: 1000;
  box-shadow: var(--shadow);
  border: none;
  animation: fadeIn 0.5s ease-in;
}
.game-over h1 {
  color: var(--food);
  font-size: 2.5rem;
  margin-bottom: 1.2rem;
  text-shadow: 0 0 10px rgba(244,63,94,0.10);
}
.game-over p {
  font-size: 1.3rem;
  margin: 0.8rem 0;
  color: var(--text-main);
}
.game-over span {
  color: var(--accent);
  font-weight: bold;
}
#restart-btn {
  margin-top: 1.5rem;
  padding: 0.8rem 2rem;
  font-size: 1.1rem;
  background: var(--accent);
  color: var(--text-light);
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s, transform 0.2s;
  text-transform: uppercase;
  letter-spacing: 1px;
  box-shadow: 0 2px 8px rgba(37,99,235,0.10);
}
#restart-btn:hover, #restart-btn:focus {
  background: var(--accent-light);
  transform: translateY(-2px) scale(1.04);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.8);
  }
  to {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
}

#head.up { transform: rotate(-90deg); }
#head.down { transform: rotate(90deg); }
#head.left { transform: rotate(180deg); }
#head.right { transform: rotate(0deg); }