Theme request: Subnotebook shading

Features
12

Thank you so much! That works perfectly.

I may darken the last color and add some more, but this is working for now:

.list-item-depth-1  {
    background-color: #213952 ;
}
.list-item-depth-2  {
    background-color: #214A6B;
}
.list-item-depth-3  {
	display:table-cell;
    background-color: #315A84;
}
.list-item-depth-4  {
    background-color: #356EA3;
}