Updated and found problems, now loading but icons changed to default color

Hi, I’ve looked here:

I updated everything on Wordpress 2 weeks ago and everything was fine. Then today when I logged on I couldn’t get in so my web host found a way in and had to walk back an update, they said it was related to Shapely, anyhow they got the site loading but the two things that were different were:

  1. The icons have gone back to default purple
  2. The blog has half the text in the same purple

I’m trying to try the solutions listed in the above posts, I had actually gotten it fixed when I set up the website 4 years ago, I don’t know if I did it the exact same way, but now I cannot work out where to put the custom CSS code, I can’t see Appearance > Customize > Shapely Options etc etc in Wordpress. And I can’t work out where it’s calling the purple from (I think that’s what I changed the first time I changed it)

I’m scared to update to WP 6.7.1 because I"m not sure if that’s what caused the problem with Shapely last time. Advice please!

This is my site: