#wrapper
{
    background-image:  linear-gradient(#000 1px, transparent 1px), linear-gradient(to right, #000 1px, #e4e4e4 1px);
    background-size: 15px 15px;
}
@media (max-width: 500px) {
    #wrapper
    {
        background-color: #dddddd;
        background-image:  linear-gradient(#000 1px, transparent 1px), linear-gradient(to right, #000 1px, #e5e5f7 1px);
        background-size: 15px 15px; 
    }
}
#defaultCanvas0{
    max-width: 100%;
    max-height: 100%;
    margin: auto;
    overflow: auto;
    position: fixed;
    object-fit: contain;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}