Flexbox full height layout width header, footer and liquid body

<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="style.css">
    <script src="script.js"></script>
  </head>

  <body>
    <div class="container">
      <div class="header">Header</div>
      
      <div class="main">
        <div class="col">Col 1</div>
        <div class="col">Col 2</div>
        <div class="col">Col 3</div>
      </div>
      
      <div class="footer">Footer</div>
    </div>
  </body>

</html>

// Code goes here

body {
  margin: 0;
}

.container {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.header {
  background-color: #f0f0f0;
  flex: 0 0 auto;
  height: 80px;
}

.main {
  background-color: #ccc;
  display: flex;
  flex-direction: row;
  flex: 1 0 auto;
}

.col {
  background-color: #ccc;
  width: 100%;
}

.footer {
  height: 80px;
  background-color: #f0f0f0;
  flex: 0 0 auto;
  width: 100%;
}