How to change style of H2?

[bboots]

I want to be able to designate a few words in a post as H2 (for the search engines) while human readers see the words looking like a normal part of the post. For example, in the sentence "The two abnormal foot structures he discovered are the Rothbarts Foot and the Preclinical Clubfoot,"I would like to tag ONLY "Rothbarts Foot" as H2.

I tried changing the style sheet so that the font size for H2 would stay the same as the font size for the post body, like this:
#content h2 {
background: #000000;
color: #FFFFFF;
font-size: 12px;
font-family: Arial, Tahoma, Verdana;
font-weight: normal;
margin: 0px 0px 0px 0px;
padding: 10px 0px 10px 10px;
}

The I put the tags around the word like this:
The two abnormal foot structures he discovered are the<h2> Rothbarts Foot </h2>and the Preclinical Clubfoot.

However, when I published the post, the entire sentence text was in the solid blue block that LIfestyle uses for H2.

What do I need to do?