html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: Arial, sans-serif;
    background: linear-gradient(to bottom, #e0eafc, #cfdef3);
}
.container {
    position: relative;
    width: 100%;
    max-width: 1200px;
    height: 100vh;
    margin: 0 auto;
    overflow: hidden;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    border-radius: 8px;
    background: #f9f9f9;
}
#container canvas {
    display: block;
}
#crosshair {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    transform: translate(-50%, -50%);
    pointer-events: none;
}
#crosshair:before, #crosshair:after {
    content: '';
    position: absolute;
    background: #333;
}
#crosshair:before {
    left: 9px; top: 0;
    width: 2px; height: 20px;
}
#crosshair:after {
    left: 0; top: 9px;
    width: 20px; height: 2px;
}
#blocker {
    position: absolute;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
}
#instructions {
    color: #fff;
    font-size: 24px;
    text-align: center;
    cursor: pointer;
}
footer {
    position: absolute;
    bottom: 10px;
    width: 100%;
    text-align: center;
    color: #555;
    font-size: 14px;
}