<div class="box-1 box">
  <p>Box 1</p>
</div>
<div class="box-2 box">
  <p>Box 2</p>
</div>

.box {
  width: 200px;
  height: 50px;
}

.box-1 {
  border: 1px solid green;
  color: green;
}

.box-2 {
  border: 1px solid blue;
  color: blue;
}