NB! make a backup before making any changes!
NB! Make your changes in a childtheme, not the original theme!
(see: https://codex.www.ads-software.com/Child_Themes)
== == ==
1. find the css-file(s) that come with the plug-in
copy and rename the css-file to ‘plugin.org.css’
This is your original copy should anything go wrong.
e.g. ../wp-content/plugins/'myplugin'/'plugin.css'
at the bottom of the css-file place the code
<!-- changed title-size -->
h1{font-size: 20px;} /*play with the sizes 20px, 24px, etc.*/
h2{font-size: 18px;}
h2{font-size: 14px;}
or
h1 {font-size: 3em;}
h2 {font-size: 2.4em;}
h3 {font-size: 1.5em;}
FYI to see which element [h1, h2, h3, title etc.] is the culprit, go to the affected page and [in IE] press <F12> It will show you the code behind the page. Make an ‘educated guess’ and alter the item.
Check the results, reset if need be and try again.
