Inline-block element height issue

Question

I have a simple example in which an outer DIV contains an inner DIV which has
display: inline-block;.
Because I have set the

Answer 1

.outer{font-size:0} will do the job

.outer {
  background-color: red;
  font-size:0 
}
.inner {
  display: inline-block;
  width: 480px;
  height: 140px;
  background-color: green;
}