Hallo everyone,
what correction do i need here to validate in W3C CSS...In my book that's how it was written.


CODE]
input:focus:valid
{
background: rgb(220,255,220) url(okay.png) bottom right no-repeat;
-o-background-size: contain;
-moz-background-size: contain;
-webkit-background-size: contain;
background-size: contain;
}
input:focus:invalid
{
background: rgb(255,232,233) url(warning.png) bottom right no-repeat;
-o-background-size: contain;
-moz-background-size: contain;
-webkit-background-size: contain;
background-size: contain;
}
[/CODE]

the error in W3C CSS are
137 Unknown pseudo-element or pseudo-class :valid
145 Unknown pseudo-element or pseudo-class :invalid

help would be greatly appreciated
thanks in advance