Screen {
    overflow: auto;
}

#paint {    
    layout: grid;
    grid-size: 2;
    grid-gutter: 1 2;
    grid-columns: 6;
    grid-rows: 3;
    margin: 1 2;
    min-height: 25;
    min-width: 26;
    height: 100%;
}

Button {
    width: 100%;
    height: 100%;
}