[Roger Coathup]

I want to do something as simple as override a few bbPress CSS selectors.

I make the mods in my theme stylesheet, but they have no effect as bbPress is injecting it’s CSS after the theme stylesheet.

Are there any instructions on how to achieve this really basic step?

It’s a fairly default bbPress install (site wide) on a BuddyPress site. Have selected the bbPress default theme package: /plugins/bbpress/bbp-theme-compat option in wp-admin

[Stephen Edgar]

Give this plugin a try if you only want to do some CSS tweaks.
https://wordpress.org/extend/plugins/bbpress-custom-css-file/

If you do want to go down the custom templates route https://codex.bbpress.org/theme-compatibility/

[Roger Coathup]

OK.. no need for a plugin.

JJJ’s default theme compat stuff first searches for a bbpress.css file in the theme’s css directory —

So, a workaround is to simply copy the bbpress.css from the theme-compat folders into a css folder in your theme, and then edit that file.