If you're a ProfitUI CE player, you can't go wrong with the Classic ProfitUI skin. And the updater also offers two other low-key choices for alternate custom skins: Fossil and Storm. But what about those default themes -- Red and Blue?
ProfitUI CE player jiimbo recently reported a display glitch when trying to use the Default_Blue theme, which reminded me that I've been promising to make Red and Blue themes work with ProfitUI CE for far too long. When the ProfitUI CE utility was initially designed, those skins were included on the Themes page to prevent a compatibility issue. But because they can't be modified they've never been viable when used without the complex ProfitUI custom graphics assets.
Now you can download and choose custom Red and Blue alternate theme packages:

Once they are downloaded, you can choose Alternate Red or Alternate Blue from the Themes page:

You'll need to completely restart the game to load up the new graphics assets after changing to a new theme. Enjoy!