Update: styles in usercss mode can be installed from URLs directly. All you need is to add a valid header in the comment at the start and increase style version on updates. Example: JishoDeepDark.user.css.

Seconded. I want to add one of the .css styles from the Minimal browser extension as a userstyle. They are essentially userstyles, but not technically "UserStyles", with a <name>.user.css file name and a ==UserStyle== header. Rather, they are just written to be used with the extension.

I have manually added the style, but whenever it is updated, I will have to manually update it.

@tophf This won't work if it's someone else's style not formatted as a proper UserStyle. You'd have to fork it, and manually update whenever the original style is updated.

I suggest Stylus allow regular .css file to be installed, and let the user specify which sites (e.g. www.youtube.com) it's supposed to run on, and then for it to update from the URL it was installed from as if that were it's @updateURL.

Perhaps this could be achieved via a special install or import option, where the user can add a .css style (which has no ==UserStyle== header) from a given URL, then a header is generated (separate from the raw CSS), with the @updateURL automatically being added based on the URL it was installed from. Or, the user could write this separate header manually.

You can probably use the standard CSS @import statement for the original URL in your local userstyle.

Is there a workaround for this? I want to have the automatically installable theme link, but I also want the user to get automatic updates to the theme

@MulverineX yes, there's an alternative available for several years: usercss. We could probably just close this issue.

I was not aware that usercss did automatic updates, it's fine then

usercss