Thank you for the kind words.
I probably won't change the borders to something else, sorry.
During development of the color scheme I experimented with a lot of backgrounds and frame borders, but I never found something that looked thematically sound but for how it looks now.
Just recently I increased frame border thickness to account for the problem you describe and have been very happy with it up until now.
Please be aware that this theme is very sensitive to screen brightness. You may want to check your monitor settings in case they are set very low. I have mine set to 120 cd/m which is well suited for dimmed/low light conditions.
I would also advice you to check if your screens contrast settings are set to a value that is ill suited for dark colors.
I may provide add-on extensions for some tweaked borders or backgrounds if you wish, but please don't hold your breath on this.
Cheers
Sir Motte
Edit: I added new frame borders that are a mix of both black and a lighter brown, which works perfectly.