we can only give you css to make font smaller or change color but within css it is not possible to change htmls tags. To do this, you must modify theme files what we do not recommend to do.
As we understand, you want to change titles for widgets. Files for widgets are under /functions/ folder you have different files for different widgets. Each file starts with widget- text. But please remember, that after any changes inside theme files, we can't be responsible for your website.
Comments
we can only give you css to make font smaller or change color but within css it is not possible to change htmls tags. To do this, you must modify theme files what we do not recommend to do.
Thanks!