body {
    margin: 0;
    overflow: hidden;
    background: #000;
}
canvas {
    display: block;
    image-rendering: pixelated;
}

/* Professional Game Over Popup */
#gameOverPopup {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.8);
    background: rgba(25, 25, 25, 0.92);
    padding: 35px 50px;
    border-radius: 14px;
    text-align: center;
    box-shadow: 0 12px 35px rgba(0, 0, 0, 0.8), inset 0 0 25px rgba(255, 255, 255, 0.05);
    color: white;
    z-index: 10;
    min-width: 320px;
    backdrop-filter: blur(10px);
    opacity: 0;
    transition: opacity 0.35s ease, transform 0.35s ease;
}

#gameOverPopup.show {
    display: block;
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
}

#gameOverPopup h1 {
    font-size: 24px;
    margin-bottom: 20px;
    font-weight: 600;
    letter-spacing: 0.5px;
}

#restartBtn {
    padding: 12px 28px;
    background: linear-gradient(135deg, #ff6600, #ff3300);
    color: white;
    font-size: 18px;
    font-weight: 600;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(255, 100, 0, 0.5);
    transition: transform 0.2s ease, background 0.3s ease;
}
#restartBtn:hover {
    background: linear-gradient(135deg, #ff8533, #ff4400);
    transform: scale(1.05);
}