Parallax Content Slide-In on Siteload


I want to create two Content Slide-Ins when the Site is loaded. One Slide-In is the transparent background an the other Slide-In is the Content. The effect should exactly be like it is on this page:

A half transparent black background sliding in from the bottom and the Content (Text and Images) sliding in from the top. How can I do that? Will I need a lightbox-plugin or similar, or can I do this with jquery? CSS3-only?

Would be awesome if you could help me with the most simple solution.