It is very likely that more specific selectors are used for the different h elements in the theme. This is typically the case, and as an example an h3 for widget titles might be styled under a class of "widget-title" instead. Same with some of the other typically used h elements in the theme design (typically h1-3) so you have to actually look at the HTML (markup for the pages and elements to see what CSS would be associated with those specific elements.
As an example, the post title on the main page is h1 and a link and under:
.entry-title a:link, .entry-title a:visited
If you click through to a single post page or to any static page (about, etc.) then the titles h1 under:
I would recommend getting Firebug for firefox (if you are using firefox) or see if there is an "inspector" in the browser you are using. IE9, Chrome and Safari have features that allow you to inspect the elements of a web page and see what HTML and CSS is associated with those elements and in most cases you can even tryout CSS changes in real time.
If what you have above is working, then that is all that is necessary at this time. Your pages look consistent to me right now. If there is something specific, let us know.