<style>
.container {
  font-family: Ahem;
  font-size: 20px;
  line-height: 0;
  background-color: green;
  color: transparent;
  width: 100px;
}
</style>
<div class=container>PASS if the line green box shows up<div style="display: inline-block; width: 0px; height: 0px;"></div></div>
