.box {
   height: 250px;
   width: 250px;
   border: solid;
   margin: 20px;
}

.red {
  background-color: red;
}

.green {
  background-color: green;
}

.blue {
  background-color: blue;
}

.black {
  background-color: black;
  color: yellow;
}

.yellow {
  background-color: yellow;
}

.pink {
  background-color: pink;
}

.cyan {
  background-color: cyan;
}

#obs {
  border-color: orange;
  border-width: 20px;
  border: solid;
}