CSS Library: Vertical CSS Menus: CSS3 demos: Here
CSS3 animated vertical slanted menu
Author: Dynamic Drive
CSS3 lets you animate virtually any CSS property, so instead of directing changing into a property, the browser slowly morphs into the new value instead. This is done via CSS3's "transition" property, which is supported in IE10+, FF3.5+, Chrome/Safari, and Opera 10+. With that introduction out of the way, this is a vertical list menu that uses CSS3 animation to gradually expand the selected menu item horizontally so to highlight it. It also employs the CSS border trick to create a cross browser slanted left edge. The final result is a sleek vertical list menu that uses nothing but pure HTML markup!
Demo (best viewed in (IE10+, FF3.5+, Chrome/Safari, and Opera 10+):