body {
    background-color: #000000; /* Nền đen */
    color: #ffffff; /* Chữ trắng */
    font-family: 'Press+Start+2P', monospace;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    overflow: hidden;
}

#game-container {
    position: relative;
    border: 3px solid #ffffff; /* Viền trắng */
    
    /* Làm cho canvas có cạnh sắc nét, không bị mờ */
    image-rendering: -moz-crisp-edges;
    image-rendering: -webkit-crisp-edges;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

canvas {
    display: block;
    background-color: #000000; /* Nền game đen */
}

#score {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 48px;
    z-index: 10;
    text-shadow: 3px 3px #000;
}

#start-message, #game-over-message {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 24px;
    text-align: center;
    line-height: 1.5;
    z-index: 10;
    text-shadow: 2px 2px #000;
}

#game-over-message span {
    font-size: 16px;
    margin-top: 10px;
    display: block;
}

.hidden {
    display: none;
}