I am making a Layout.
.container{
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100vh;
  background-color: gray;
}
.header{
  width: 100%;
  height: 80px;
  background-color: red;
}
.content{
  align-self: stretch;
  width: 100%;
  background-color: blue;
}<div class="container">
  <div class="header">
    Header
  </div>
  <div class="content">
    Be filled the rest part
  </div> 
</div>What I expect
Condition
I don't want to use calc() in CSS because header's height could be dynamic.

 
    