I haven't used themes since I found the built-in dark mode. I went to the add-on page to check something, saw this recommended, and I love it! This theme keeps the dark theme aesthetic, and has the perfect shade of turquoise! The background image also does a great job of looking nice while staying out of the way so I can still see my toolbar buttons.
Indeed, when i created this, i tried to make it a dark theme but with a quite cold aspect. I created the background picture with the open-source software The Gimp. I am really happy if you enjoy this theme :) ! Thank you for your comment SuperSluether :) !