Board Thread:Support Requests - Getting Technical/@comment-45820645-20200618195821

Hey, I've an infobox over here. I've updated the CSS format, but where would I put the code to edit font size, colour etc? In the old infobox format the first line was like this:

cl ass="info box" style="fon t-size:89%; wid th:300px; tabl e-lay out:fixed; back gro und-color:#FFF;"

Where would I put such code in the new infobox format? Thanks!  