how to make a CSS controlled background gradient

Hi all,

I think I came across it a while ago, but I can not find it now. There was this trick on how to make a CSS gradient background,

it was something like

background-color: #123456 50%;

or something like it. That thing is supposed to fill up a table cell or an entire page with gradient background, if anybody knows what I am saying, assist me, please. I wish I could describe it better than that, but I don't think I can!

Thank you,

Chris