example.css

    html {
      background: #F7F7F7;
      color: red;
      height: 100%;
    }
    body {
      min-height: 100%;
    }
    
    .wrapper {
      min-height: 100%;
      display: flex;
      flex-direction: column;
    }
    
    .content {
       flex: 1 0 auto;
    }