*
{
    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;
}