Works even on Big and High Resolution Screens (tested on a 2560x1440 Display).
Looks nice but the text contrast on the bookmark bar could be better.

Here is a link to my Themecollection:
https://addons.mozilla.org/de/firefox/collections/13329745/Xenofox-Themecollection/

Cool, but not dark on the new tab background & menu

Works for android as well, but not my personal taste