div
{
height:100px;
width:100px;
border-radius:50%;
margin: auto;
margin-bottom:15px;
}
#redbox
{
  background:red;
}

#orangebox
{
  background:orange;
}
 #yellowbox
{
  background:yellow;
}

#greenbox
{
background: green;
}
#bluebox
{
  background:blue;
}

#violetbox
{
background: violet;
}