How to reduce size of titles in articles

How can I reduce the size of the title in articles when showed in category blog.
It seems they are now H1 size and I like to reduce this size to H3 or H4.

Another problem occured after installing JCE 2.0 In the description of any article I don't have a blank (white) field, but the background of the website appears. In the front end everything is normal.

Thanks for quick response.

Hi

Please show me a page where this titles are and send me an access to joomla panel.

Hi

Please add this code to css:

Code: Select all

.itemToolbar .contentheading {
    font-size: 30px;
}