body, html {
        margin: 0;
        padding: 0;
        width: 100%;
        height: 100%;
        overflow: hidden;
        background-color: #1a1a1a; /* Dark background to highlight neon elements */
        cursor: none;
        font-family: 'Orbitron', sans-serif; /* Retro font */
    }
    #gameCanvas, #shaderCanvas {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
    }
    #hud {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        display: flex;
        justify-content: space-around;
        padding: 10px;
        background: rgba(0, 0, 0, 0.5);
        z-index: 2;
    }
    #score, #highScore, #level, #speed, #gravity, #lives {
        padding: 10px;
        font-size: 18px;
        font-weight: bold;
        color: #00FFFF; /* Neon cyan */
        text-shadow: 0 0 10px #00FFFF;
        border: 1px dashed #FFD700; /* Retro gold */
        border-radius: 8px;
        background: rgba(0, 0, 0, 0.8);
        box-shadow: 0 0 15px #FFD700;
    }
    #lives {
        color: #FF69B4; /* Neon pink */
        text-shadow: 0 0 10px #FF69B4;
    }
    #shieldContainer {
        width: 200px;
        height: 20px;
        background-color: rgba(0, 0, 0, 0.7);
        border: 1px solid #00FFFF; /* Neon cyan */
        position: absolute;
        left: 20px; /* Below score element */
        top: 60px;
        border-radius: 10px;
        overflow: hidden;
        margin-top: 10px;
    }
    #shieldBar {
        height: 100%;
        width: 100%;
        background-color: #00FF00; /* Neon green */
        transition: width 0.3s ease-out;
        box-shadow: 0 0 10px #00FF00;
    }
    #shieldText {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        text-align: center;
        line-height: 20px;
        color: #000;
        text-shadow: 0 0 2px #00FF00;
    }
    #shieldAlert {
        display: none;
        position: absolute;
        top: 80px;
        left: 20px;
        background-color: rgba(255, 0, 0, 0.7);
        color: white;
        padding: 5px;
        border-radius: 5px;
        border: 1px solid red;
        z-index: 3;
    }
    .right-instructions {
        position: fixed;
        bottom: 20px;
        right: 20px;
        width: 300px; /* Adjust width as needed */
        background-color: rgba(0, 0, 0, 0.8);
        padding: 20px;
        border-radius: 10px;
        z-index: 1000;
        display: block; /* Ensure instructions are visible by default */
    }
    .right-instructions h2, .right-instructions li {
        color: #00FFFF; /* Neon cyan */
    }
    #toggleInstructions {
        position: fixed;
        bottom: 20px;
        right: 340px; /* Positioned to the left of the instructions */
        z-index: 1001;
        padding: 10px 20px;
        background-color: #00FFFF; /* Neon cyan for retro feel */
        color: #1a1a1a;
        border: none;
        border-radius: 5px;
        cursor: pointer;
        font-family: 'Orbitron', sans-serif;
        box-shadow: 0 0 10px #00FFFF;
        transition: background-color 0.3s;
    }
    #toggleInstructions:hover {
        background-color: #00e6e6;
    }
    .low-shield {
        animation: blinkRedGlow 0.5s infinite;
    }
    @keyframes blinkRedGlow {
        0%, 100% { filter: drop-shadow(0 0 5px rgba(255, 0, 0, 0.7)); }
        50% { filter: drop-shadow(0 0 15px rgba(255, 0, 0, 0.9)); }
    }
    .score-increase {
        color: #FFD700; /* Retro gold */
        text-shadow: 0 0 5px #FFD700;
    }