fix transparent header to white header transition for non-fullscreen articles
fix transparent header to white header transition for non-fullscreen articles

artsy/force,kanaabe/force,xtina-starr/force,erikdstock/force,artsy/force,xtina-starr/force,izakp/force,joeyAghion/force,erikdstock/force,damassi/force,mzikherman/force,kanaabe/force,cavvia/force-1,xtina-starr/force,izakp/force,yuki24/force,cavvia/force-1,kanaabe/force,erikdstock/force,yuki24/force,joeyAghion/force,anandaroop/force,cavvia/force-1,kanaabe/force,kanaabe/force,artsy/force,artsy/force-public,yuki24/force,eessex/force,damassi/force,dblock/force,dblock/force,anandaroop/force,oxaudo/force,oxaudo/force,oxaudo/force,yuki24/force,anandaroop/force,oxaudo/force,anandaroop/force,cavvia/force-1,artsy/force,eessex/force,izakp/force,eessex/force,dblock/force,erikdstock/force,artsy/force-public,damassi/force,mzikherman/force,izakp/force,damassi/force,joeyAghion/force,eessex/force,joeyAghion/force,mzikherman/force,mzikherman/force,xtina-starr/force