On the Upgrading theme help pages, when it says "Create a new ID for the "#admin_menu_anim object" " etc., does this mean create a new code bit like all the others, eg ".thumb_title { font-weight : bold; font-size: 80%; padding: 2px; display : block; }"
Why do I need to validate my css files?
Yes.
You don't have to validate them... no one will arrest you. Validation just increases the likelihood that your site will look okay across different browsers. Non-standard code tends to "break" on different browsers.
thanks very much :)