LEVEL #1
LEVEL #2-1
z-index: 4;
LEVEL #3-1
LEVEL #3-1
LEVEL #3-1
LEVEL #3-1
LEVEL #3-1
LEVEL #2-2
z-index: 3;
LEVEL #3-2
LEVEL #3-2
LEVEL #3-2
LEVEL #3-2
LEVEL #3-2
LEVEL #2-3
z-index: 2;
LEVEL #2-4
z-index: 1;
LEVEL #1
LEVEL #1
LEVEL #1