This is the teambuilder I use to build teams, I like it a lot and find it very eye-soothing so I wanted to share it with other users.
As the name indicates it's a dark theme which affects only the teambuilder related parts of Pokemon Showdown, this theme affects Smogon University(main) and all "psim.us" servers.
If you like this style, don't hesitate to drop a like and positive comment, and if you have any issues with this theme or any bugs, you can find me at a server such as Wisp under the name @Master Float.