Created attachment 273214 [details]
zoomed image of videos with a line below the headerbar gives 

The line just below the gtk-headerbar adds blur and doesn't feel right to the eye. Please see the attachements; 

attachment 1 [details] is the zoomed image of the current videos interface, with a line below headerbar.

attachment 2 [details] normal window with the line below headerbar, which makes the headerbar look bigger and blurry.

attachment 3 [details] is line removed (edited using gimp); looks good to the eye and the element of blur and a feel of big headerbar is gone.

attachment 4 [details] is smplayer, the title bar and video has no space.

attachment 5 [details] is our nautilus, we can see that there's no line below headerbar.

attachment 6 [details] is nautilus in dark theme, there is also no line below headerbar.

Please consider removing the line below headerbar for visual clarity. thanks.