Advice for light barrier, closet setup with passive intake

So I'm going to be starting my second grow with some white widow bag seed in a closet in my office. Same closet as my pretty successful L.S.D. first grow. Now 90% of the people who come into my office know I smoke, so smell isn't as much of an issue, even though I have it covered with filters and ona gel. I just don't want light beaming out of the bottom of the closet like last time. I had a light-blocking tarp covering the top 3/4 of the door's inner frame, and a stick-on zipper access. The bottom third was passive intake which let air in but light out. The fan exhausts (one small one on the light, large one on the can filteR) vented out the top of the closet. with the door shut there was no airflow. Unfortunately the closet walls are cement inside, which means no construction to push air into the attic, etc.

Anyone have a good configuration to solve this problem? I worry a little about blocking too much airflow with a light baffle... things got pretty hot last time, although it's winter now. I think that I need to rig my big fan directly to my light (I had it just running through a homemade can filter before.)