As @gskema it is a good idea to copy or follow some frameworks styles for fonts, but it won't always help you if you use a special font for your site. The things that I've been reading about usability and readability is that the minimum font size that you can use for users to read it without any difficulty is 16px, that should be your base and minimum size, but as always it depends on every font, some are naturally bigger than others but that's kind of a standard. You could put your body to be at default 16px and then use ems to change sizes for desktop and stuff.
Also never use line-height at 100% or 1 use it at 120% or 130% for it to be easier to read. Hope this work for you.