This repository contains Zotero userChrome.css files using the Catppuccin palettes.
It has only been tested on Zotero 7 on Linux Mint 22 but should work for previous versions.
In Zotero 7, you need to change the "toolkit.legacyUserProfileCustomizations.stylesheets" flag to true for this (and any other) theme to work:
Go to Edit → Settings
Click on Advanced
Scroll down, find and click on "Config Editor".
search for the flag "toolkit.legacyUserProfileCustomizations.stylesheets" and set it to True.
Close Zotero
Then, copy the theme into your Zotero user profile folder:
Go to your user Profile folder
Windows users: C:\Users\User_name\AppData\Roaming\Zotero\Zotero\Profiles\user_profile.default\
Linux (Flatpak) users: ~/.zotero/zotero/XXXXXXXX.default/
Create a folder called "chrome"
Place the userChrome.css file of your preferred flavour in there
Start Zotero and enjoy