I have installed Material Theme UI and it made my IDE blackish. Later I decided to remove and and removed plugin. Unfortunately, this didn't give default colors back, some parts of IDE, for example Project pane, remained blackish.
How ro recover?
How to remove material theme from IntelliJ / PyCharm?
you can go to the Preferences->Plugins on the search bar, type Material UI then press on the Uninstall button .