I surmise you intend this to be a desk/computer table. If it were me, I'd put diagonal braces under the points where your green dots are. The wide part of the brace should be right under the desktop and span from the wall to about 8 inches from the front edge of the desktop. The narrow part, of course, should be on the floor and span about 8-10 inches from the wall. If you wanted to be fancy, you could cut an arc instead of a straight line from top to bottom. Either should give you adequate knee and toe room and hold the top rigidly enough to carry the weight of the desktop, the computer and other things that may be there.
I see there are legs along the back edge but it might also be necessary to install a ledger board under the back edge of the desktop to fasten it to the wall.
Last edited by 163481; 08-21-2015 at 06:10 PM.