add this to custom css

#wpforo #wpforo-wrap .wpforo-post .wpforo-post-content p,
#wpforo #wpforo-wrap .wpforo-post .wpforo-post-content span {
 color: inherit !important;
 font-size: inherit !important;
}

Dashboard > Forums > Settings > Style (custom css)

We have a growing forum and the software and the additional paid wpforo add-ons are working out pretty well. We have also successfully "hidden" both the font size and font color options from the editor. However...people are still able to cut and paste all sorts of colors and different font sizes. This makes a very chaotic messy looking forum. I need to find a way to "force" all post content to be a certain size font and also font color. Ideally, this could be done via css but I have tried to come up with a solution repeatedly via css, but I have not yet found way from preventing someone from copying and pasting and posting huge text and multiple colors. Does anyone have any ideas? Surely this can be done somehow. See the attached screenshot as an example of font sizes and color from a post that needs to be changed. How would we force this user from posting colors and span style sizes?? Surely there's a way...

Thanks!