círculo CSS
#circle {
width: 100px;
height: 100px;
background: red;
border-radius: 50%
}
Combative Cowfish
#circle {
width: 100px;
height: 100px;
background: red;
border-radius: 50%
}
#circle {
width: 100px;
height: 100px;
background: red;
border-radius: 50%
}<div id="circle">
</div>
#circle {
width: 100px;
height: 100px;
background: red;
border-radius: 50%
}