Slide down animation from display:none to display:block?

Yes, there is a way:
http://jsfiddle.net/6C42Q/12/

By using CSS3 transitions, and manipulate height, rather than display property:

.hidden {
    height: 0px;
    -webkit-transition: height 0.5s linear;
       -moz-transition: height 0.5s linear;
        -ms-transition: height 0.5s linear;
         -o-transition: height 0.5s linear;
            transition: height 0.5s linear;
}

.hidden.open {
     height: 200px;
     -webkit-transition: height 0.5s linear;
        -moz-transition: height 0.5s linear;
         -ms-transition: height 0.5s linear;
          -o-transition: height 0.5s linear;
             transition: height 0.5s linear;
}

More here: Slide down div on click Pure CSS?