Property transition doesn't exist

Hy.

I have this error while validanting my css:

 



 

 

..site-header .header-info ul {

                float: right;

                padding-bottom: 20px;

                list-style: none;

                transition: all 400;

                -webkit-transition: all 400;

                -moz-transition: all 400;

                -o-transition: all 400;

}

 

And also if I set in this othe way:



..site-header .header-info ul {

                float: right;

                padding-bottom: 20px;

                list-style: none;

                transition: all 400ms;

                -webkit-transition: all 400ms;

                -moz-transition: all 400ms;

                -o-transition: all 400ms;

}

 

What's the matter?

 

Thanks

 

Andrea Nenci