Sloped Floor: Quick Fix for Bed and Desk
Build a large "ramp" that has the same angle as the slope in the room. When the ramp is placed on the floor, the top of the ramp will be level. The high part of the ramp will probably be against the wall in your case, where the desk would sit. The low part would be out in the room and would be where your chair would go. You'll have to be careful not to wheel the chair off of the ramp, so you may want to add a small "curb". The tough part will be getting the angle right, but it doesn't need to be exact; in your case, any improvement may be better than what you have now