The HTML for that page has quite a few errors, so it's hard to identify the specific issue. Start by removing the <ul> and <li> elements for posts. It's just going to keep throwing off your layout because browsers don't expect to see <div> and <center> tags between <ul></ul>. While you might see multiple posts as a part of a list, that's really not the kind of list <ul> is meant to handle. Just use nested <div>s instead. Try to do some more studying of HTML and CSS and then take another shot at this page.