*
{
    margin: 0;
    padding: 0;
}

html,
body
{
    overflow: hidden;
}

.webgl
{
    position: fixed;
    top: 0;
    left: 0;
    outline: none;
}
.serve-btn {
    position: absolute;
    top: 20px;  
    left: 20px;
    padding: 10px 20px;
    font-size: 16px;
    z-index: 1;
    cursor: pointer;
}