UddeIM message font too small and icons appear only as tiny dots

Chapter 12 does not tell me where to find the CSS or how to change the font or icons. I'm sadly still as clueless as before. Even more so now that I know the place I was looking was wrong lol

I don't know where to look for the CSS file, I think that's the main issue. I keep reading to change it which is great, but if I can't find it, it's not so great.

Can you possibly point me in the correct direction?
If I am to change the template css code for the messages section in the default template I need to know where it is. Everything leads to the last screenshot I sent which is where I can get to the Custom scss and css components but it tells me they are generated by gantry 5 and any changes will be lost, also it tells me to check their recommendations on altering css files which says to alter the custom css file, but the custom file also says all changes will be lost.

It's a never ending loop of no answers.

I appreciate your patience, and also appreciate the help.