<html>
<head>
<style>
.inlineblock {
  display: inline-block;
  background-color: green;
}

.child {
  display: block;
  margin: 1em;
  background-color:yellow;
  width:100px;
  height:100px;
}
</style>
</head>
<body>
<p><span class="inlineblock"><span class="child"></span></span></p>