body {
    margin: 0;
    background: linear-gradient(to bottom, #1c1c1c, #2d2d2d);
    color: #eee;
    font-family: 'Segoe UI', sans-serif;
    text-align: center;
}

canvas {
    background: radial-gradient(circle at center, #444 0%, #222 100%);
    display: block;
    margin: 20px auto;
    border: 4px solid #555;
    box-shadow: 0 0 20px #000;
    border-radius: 10px;
}

#startMenu, #gameOverScreen, #leaderboard {
    position: fixed;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.85);
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

#startMenu input, #startMenu button,
#gameOverScreen button, #leaderboard button {
    margin: 8px;
    padding: 12px 20px;
    font-size: 18px;
    border-radius: 8px;
    border: none;
    background: linear-gradient(to right, #0af, #08c);
    color: white;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}

#startMenu input {
    background: #333;
    border: 1px solid #666;
    color: #fff;
}

button:hover {
    background: linear-gradient(to right, #08c, #06a);
    transform: scale(1.05);
}

h2, h3 {
    color: #0cf;
    text-shadow: 0 0 10px #0cf;
}

#helpBox {
    display: none;
    position: fixed;
    top: 60px;
    right: 10px;
    background: rgba(60,60,60,0.95);
    color: #fff;
    padding: 15px;
    border: 2px solid #888;
    border-radius: 10px;
    z-index: 2000;
    box-shadow: 0 0 10px #000;
}

#leaderboard {
    border-radius: 12px;
    box-shadow: 0 0 20px #0ff;
    max-width: 400px;
    text-align: left;
}

#leaderboardList {
    list-style: none;
    padding: 0;
    margin: 10px 0;
    width: 100%;
}

#leaderboardList li {
    padding: 5px 10px;
    border-bottom: 1px solid #444;
}