Smaller inline latex fonts?

[borgauf]

First-day noob here. I found this in the html version of my file

.MathJax_Display,
.MathJax {
border: 0 !important;
font-size: 100% !important;
text-align: center !important;
margin: 0em !important;
line-height: 2.25 !important;
}

I changed the font-size to 80% and it reduced the inline latex font size mismatch appropriately. Is there a jupytertheme to do this? BTW, is a .jupyter/custom/custom.css file compatible with jupyterthemes? Could I just make the tweak there?