I am using this on Waterfox 55.2.0, a very nice theme that looks good on my screen.

The dark rich colours of your themes put you at number 1

I love Addeludde's work - just what I was looking for. Horizontal continuity, simple but well-matched colours and textures, high-lighting and complementing text and icons.
Addeludde, I think I owe you a review and rating for all your themes I've downloaded, so apologies for the repetitivennes

Is that what the bar images are called gradients? Very nice good smoothing.