Looks pretty and smooth.

Not so good. The image has jpeg artifacts

This theme has been the smartest and clean looking theme I've found on Firefox. However, I have only two issues(these are not feature suggestions) -
1) All other texts apart from the domain(for example, "example" in www.example.com/en-US/examplehtml/html/ are all greyed out making them virtually unreadable. This is a deal breaker for me.
2) Although this is not an issue as such, it would be much nicer and less distracting if the "sudden" contrast straight vertical line could be smoothed out. The "line" I am talking about is the dividing line between the dark blue and pink area at the top left.

The theme looks great, but it only seems to cover about half the tab bar on a 4k monitor.

Gorgeous.