Inspecting one of these buttons with the devtools, I see,
...so I think the font-family: Arial !important; is overriding the custom font used for icons!
That seems a super useful observation. Since not knowing .css is one of my great weaknesses, is there an easy expression to say "don't override Font Awesome 5 Free" but do override everything else?
(Barring that, you know a good resource to learn .css quickly?)
html, body {
font-family: "consolas" !important;
}
div, span, a {
font-family: "consolas";
}
Is what I used on my own theme when testing something, it changes the "important" font areas like the sidebar and notelist but leaves the icons and most of the extra controls alone which I then targeted manually.
As for resouces to learn - I would go through the first two of these courses (I think the HTML one is important to really understand what the CSS is doing).