Issues with setting up ajax comments

Thanks again for the additional help and guidance!

I’ve been reading and searching for CSS to paste that would improve the layout even just a little.

However, as I’m not familiar with CSS/styling (other than pasting existing CSS), I would like to make very basic modifications to the styling of the imported comments. Namely, to use smaller avatar images beside the discourse usernames in the comments and add a horizontal line between posts:

Is that something simple enough that I can paste some code into /admin/customize/themes/1/common/scss/edit ?

Edit:
For anyone else, I was able to solve gravatar resize using the code here:

2 Likes