Twenty Ten header font

Greetings,

I was able to figure out how to change the font on the twenty ten theme, which is the one in use on my blog: https://www.economicthought.net

However, I don’t really understand the difference between all the code. As you can see, I just changed all the fonts to “Minion Pro Med”.

body,
input,
textarea,
.page-title span,
.pingback a.url {
	font-family: "Minion Pro Med", Georgia, "Bitstream Charter", serif;
}
h3#comments-title,
h3#reply-title,
#access .menu,
#access div.menu ul,
#cancel-comment-reply-link,
.form-allowed-tags,
#site-info,
#site-title,
#wp-calendar,
.comment-meta,
.comment-body tr th,
.comment-body thead th,
.entry-content label,
.entry-content tr th,
.entry-content thead th,
.entry-meta,
.entry-title,
.entry-utility,
#respond label,
.navigation,
.page-title,
.pingback p,
.reply,
.widget-title,
.wp-caption-text,
input[type=submit] {
	font-family: "Minion Pro Med", "Helvetica Neue", Arial, Helvetica, "Nimbus Sans L", sans-serif;
}
pre {
	font-family: "Minion Pro Med", "Courier 10 Pitch", Courier, monospace;
}
code {
	font-family: "Minion Pro Med", Monaco, Consolas, "Andale Mono", "DejaVu Sans Mono", monospace;
}

I want to keep the body as minion pro med, but I’d like to set the post headers (the post titles) to a different font. How would I do that?

Thank you.