.btn{
border:2px solid;
}
#btn1{
border:5px solid;
color:red;
}
#btn2{
border:5px solid;
color:red;
}
.clss1{
margin:auto;
padding:auto;	
	
}
.clss2{
margin:auto;
padding-top:20px;	

	
}

#donghua{
width:100px;
height:100px;
background:red;
position:relative;
animation:mymove 5s infinite;
	
}

@keyframes mymove
{
0%   {top:0px; left:0px; background:red;width:100px;}
25%  {top:0px; left:100px; background:blue;width:300px;}
50%  {top:100px; left:100px; background:yellow;width:600px;}
75%  {top:100px; left:0px; background:green;width:200px;}
100% {top:0px; left:0px; background:red;width:100px;}
}

#guodu{
width:100px;
height:100px;
background:blue;
transition:width 2s;
-moz-transition:width 2s; /* Firefox 4 */
-webkit-transition:width 2s; /* Safari and Chrome */
-o-transition:width 2s; /* Opera */
}

#guodu:hover
{
width:600px;
background:yellow;
}

 a:hover{
  background-color:aqua;
  }