#sadown{
animation-name:pulsate;
animation-timing-function:linear;
animation-delay:5s;
animation-duration:2s;
animation-iteration-count:infinite;

}

 @keyframes pulsate { 
0%{margin-top:0px;}
25%{margin-top:5px;}
50%{margin-top:0px;}
75%{margin-top:-5px;}
100%{margin-top:0px;}
}

