Are you sure the items you mentioned <li class="about"> <li class="blog"> <li class="contact"> are what this is about? Normally a horizontal list that has drodowns (vertical list) are menus. The li's you mention may be better off as paragraphs: <p>.
If menus are what you are looking or check out this tutorial( it maybe a little out of date?) http://www.htmldog.com/articles/suckerfish/dropdowns/