/* Version 1.11 */

body {
    margin: 0;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: rgba(0, 0, 0, 0.8);
    overflow: hidden;
}

#container {
    width: 100vw;
    height: 100vh;
    background: radial-gradient(circle at top left, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0) 30%), 
                radial-gradient(circle at top right, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0) 30%), 
                radial-gradient(circle at bottom left, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0) 30%), 
                radial-gradient(circle at bottom right, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0) 30%);
    background-color: lightblue;
    position: relative;
    overflow: hidden;
}

.ball {
    position: absolute;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    cursor: grab;
    background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0) 60%), 
                radial-gradient(circle at 70% 70%, rgba(0, 0, 0, 0.3), rgba(0, 0, 0, 0) 70%);
}

#ball1 {
    background-color: red;
}

#ball2 {
    background-color: blue;
}

#ball3 {
    background-color: yellow;
}

#startButton {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 20px;
    font-size: 24px;
    background-color: #fff;
    border: none;
    cursor: pointer;
}

.version {
    position: absolute;
    top: 0;
    right: 0;
    font-size: 10px;
    color: #fff;
}