div
{
  height: 100px;
  width: 100px;
  border-radius: 50%;
  margin: auto;
  margin-bottom: 10px;
}
#redBox
{
  background: red;
}

#orangeBox
{
  background: orange;
}
#yellowBox
{
  background: yellow;
}
#greenBox
{
  background: green;
}

#blueBox
{
  background: blue;
}

#violetBox
{
  background: violet;
}