And to fix the <li> validation just remove the opening and closing LI tag on line 55/56 as you don't need them, the document will then validate as XHTML strict (I've tried it)
so it should just read: <ul><li class="page_item"><a href="
http://pinkforgirls.co.uk/?page_id=2" title="Why Pinkforgirls?">Why Pinkforgirls?</a></li></ul>