#red-box
{
  background:red;
}

#orange-box
{
  background:orange;
}

#yellow-box
{
  background:yellow;
}

#green-box
{
  background:green;
}

#blue-box
{
  background:blue;
}

#violet-box
{
  background:violet;
}

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