macOS Enhancement

[jackddouglas]

This is by far the best Firefox theme I've found and am impressed that it works so well with macOS, however I ran into a small but annoying bug when resizing the window so it takes up the whole screen. A thin black bar, 8px in height, spanned the top of the window. It could be made to go away by creatively resizing the windows but even then it would work only some of the time. After inspecting the code and browser toolbox, I found three lines of code that don't seem to beneficially affect the UI in any way, at least on macOS and Windows where I've tested it. For anyone having this issue on macOS, or just to improve the overall compatibility of the code, the three lines from 73 to 75 as seen below should be removed.

Keep up the great work and thank you for sharing this great code!