I enjoyed it for a long while but it seems to have changed recently, maybe as a result of changes to Firefox rather than the theme itself. The buttons used to have a translucent white backing to them (still visible in the preview picture but not live) which made them and especially their icons pop. Now they blend in a little too well and I can't always tells what the icon is.

The theme is using its "Private browser" theme for the regular window. Its not the bright colours but the darker one. Annoying as I can't quickly differentiate between the two windows. I have tried refreshing the browser already and no difference.

Installing this addon creates a copy called "Firefox Radiance" which looks the same with a slight difference in the tab colour.