body
{
    overflow: hidden;
    margin: 0;
}

#UI-layer 
{
    position: absolute;
    z-index: 3;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
#game-layer 
{ 
    position: absolute;
    z-index: 2;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    
}
#background-layer
{
    position: absolute;
    z-index: 1;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: blue;
}