body {
    margin: 0;
    background-color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    overflow: hidden;
    font-family: sans-serif;
}

#game-container {
    position: relative;
    box-shadow: 0 0 20px rgba(0,0,0,0.5);
}

canvas {
    background: linear-gradient(to bottom, #87CEEB 0%, #87CEEB 50%, #555 50%, #555 100%); /* 空と地面 */
    display: block;
}

#ui {
    position: absolute;
    top: 10px;
    width: 100%;
    text-align: center;
    color: white;
    pointer-events: none;
}

#score {
    font-size: 32px;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}