<div class="wrapper">
  <div class="block">
    <pre>
div {
  margin-left: -50px;
}
    </pre>
  </div>
</div>

.wrapper {
  margin-left: 80px;
  background-color: #989;
  height: 350px;
}

.block {
  width: 250px;
  height: 180px;
  background-color: #eee;
  border: 2px solid #666;
  font-family: monospace;
  padding: 25px;
  margin-left: -50px;
  box-sizing: border-box;
}