css circle border

1
2    #circle {
3      width: 100px;
4      height: 100px;
5      background: red;
6      border-radius: 50%
7    }
8  

1.circle {
2    background-color:#fff;
3    border:1px solid red;    
4    height:100px;
5    border-radius:50%;
6    -moz-border-radius:50%;
7    -webkit-border-radius:50%;
8    width:100px;
9}
10<div class="circle"></div>

1#rcorners {
2  border-radius: 25px;
3}