edit size of text for Related Products

testsitepro.biz/tapware/product/4-lauren-bath-outlet-150mm
-- Joomla version -- : 3.x
I know this is an easy question. when I inspect element the text is H2 [too big for my liking] but the Hikashop Content module for Related Products says the header tag should be H3 [what I want]. I have looked thru the demo page and thru the forum and after a few hours of looking reckon I missing something. so can you put me out of my misery pls and explain how the size of this text is controlled. I also could not find anything in custom.css for front end.

Hi,
Using some CSS code like this will probably do the job :

many thanx. actually this worked:
#hikashop_submodules h2 {
font-size: 22px;
}

but what you said explained what was reqd so very happy. great support as usual.