<div class="bfc-demo-1">
  <div class="box"></div>
  <div class="box"></div>
</div>

.bfc-demo-1 {
  display: flow-root;
}
.bfc-demo-1 .box {
  width: 100px;
  height: 100px;
  background: #add8e6;
  margin: 10px;
}