text showing different sizes different areas of page, both just tags…

You didn’t exactly specify which text – there’s text all over that page. Which part?

https://computethis.com.au/wp-content/uploads/2013/12/Capture1.png

Firebug shows this for the first section CSS:

#content .post-in .desc {
    font-size: 12px;
    line-height: 21px;
}

Second section:

#content .post {
    font-size: 11px;
    line-height: 18px;
}