body, html {
  margin: 0; padding: 0; overflow: hidden; background: #0f0f0f;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
canvas {
  display: block; background: #1e1e1e; margin: 0 auto;
}
#ui, #highscore {
  position: absolute;
  left: 20px;
  color: white;
  font-size: 18px;
  user-select: none;
  z-index: 10;
  background: rgba(20, 20, 20, 0.6);
  padding: 8px 12px;
  border-radius: 10px;
  backdrop-filter: blur(4px);
}
#ui {
  top: 10px;
}
#highscore {
  top: 50px;
  color: #00ff99;
}
#instructions {
  position: absolute;
  top: 10px;
  right: 20px;
  color: #ddd;
  font-size: 14px;
  line-height: 1.6;
  background: rgba(0,0,0,0.5);
  padding: 12px 16px;
  border-radius: 12px;
  max-width: 220px;
  user-select: none;
  z-index: 10;
  box-shadow: 0 0 10px rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
}
#instructions p {
  margin: 0 0 6px;
}
#menu {
  position: absolute;
  top: 100px;
  left: 20px;
  user-select: none;
  z-index: 10;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
#menu button {
  padding: 10px 20px;
  font-size: 15px;
  cursor: pointer;
  border-radius: 8px;
  border: none;
  background: linear-gradient(135deg, #007bff, #0056b3);
  color: white;
  box-shadow: 0 4px 10px rgba(0,0,0,0.4);
  transition: transform 0.2s, background 0.3s;
}
#menu button:hover {
  background: linear-gradient(135deg, #0056b3, #003f7f);
  transform: translateY(-2px);
}
#overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.85);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  color: white; font-size: 24px;
  user-select: none; z-index: 20;
  text-align: center;
  padding: 20px;
}
#overlay h1 {
  font-size: 44px;
  margin-bottom: 20px;
}
#overlay button {
  margin-top: 20px;
  padding: 14px 28px;
  font-size: 20px;
  border: none;
  border-radius: 8px;
  background: linear-gradient(135deg, #00cc66, #00994d);
  color: white;
  cursor: pointer;
  box-shadow: 0 4px 10px rgba(0,0,0,0.4);
  transition: background 0.3s, transform 0.2s;
}
#overlay button:hover {
  background: linear-gradient(135deg, #00a653, #007f3a);
  transform: translateY(-2px);
}