.reddot {
display: block;
background: #f00;
border-radius: 50%;
width: 11px;
height: 11px;
top: 0px;
right: 0px;
}
.greendot {
display: block;
background: green;
border-radius: 50%;
width: 11px;
height:11px;
top: 0px;
right: 0px;
}
如下: