After a lot of searching, the simplest way to add RTL (right to left, Hebrew, Arabic) support in Flarum seems to be to add the following CSS to the custom CSS.
*{
unicode-bidi: plaintext;
text-align: start;
}
This relies on the browser to correctly parse what should be RTL, but it seems to work for me, including in sentences with mixed Hebrew/English.
It is not a fully-fledged RTL version of Flarum, of course. It just allows users who are more comfortable writing in RTL to do so without hassle.
So I just thought I'd post this here in case it helps anyone.
And also, happy to hear if anyone thinks this is a bad idea, or has a better suggestion. It's the best I could find for now.
