Userstyles

Userstyles allows you to inject CSS on the Scratch website - useful to make the buttons you add with userscripts colorful, or to customize native Scratch element.

How do I add a userstyle?

Make sure to refresh Scratch Addons from chrome://extensions after doing any changes to your addon.
Go to the manifest of your addon (addon.json) and add a property called "userstyles".
This property must be an array.
Each item of the array must have the following properties: "url" and "matches".
"url" must be a relative URL to a CSS file.
"matches" must be an array of URLs where you want the userstyle to be injected. You can use asterisks. Example manifest:

{
  "name": "Scratch Messaging",
  "description": "Provides easy reading and replying to your Scratch messages.",
  "userstyles": [
    {
      "url": "userstyle.css",
      "matches": ["https://scratch.mit.edu/*"]
    },
    {
      "url": "second_userstyle.css",
      "matches": ["https://scratch.mit.edu/projects/*", "https://scratch.mit.edu/users/*"]
    }
  ],
  "tags": ["community"],
  "enabledByDefault": false
}

Debugging userstyles

Make sure to refresh Scratch Addons from chrome://extensions after doing any changes to your addon.
If you don’t see your userstyle working, make sure your addon is enabled.
If you’re still having trouble, please create an issue in this repo.