The font color, size & font type are set in the CSS. You can change by using the jdownloads-custom.css to set your own.
Please see http://www.jdownloads.net/documentation-for-jd3-2/layouts-v3-2/custom-css-in-layoutsNB
I have not yet updated to jD 3.9 but there is no real change
font-colour is taken from that used in your front end template (except in one place in the Summary display)
font-size is set in many places so to help further let us know where you particularly want to change it
font-family is set in a few places it is usually font-family:Arial, Helvetica, sans-serif;
but in a couple of places it is set as font-family: "Open Sans",sans-serif;
If you let me know what you are seeking then I will try to help