example.css

    /* color */
    .container{ 
      background-color: #497bad;      
    }

    @media (min-width: 40rem) { 
      .container{ background-color: #017bad; }
    }
     
    @media (min-width: 64rem) { 
      .container{ background-color: #997bad; }
    }    

    .row{
      border: 2px solid rgba(255,255,255,0.2);
      background-color: rgba(225,255,255,0.1);
    }
    .column{
      background-color: rgba(225,255,255,0.1);
      border: 2px solid rgba(255,255,255,0.2);
    }
    .column.flow-opposite { background-color: rgba(215, 44, 44, 0.2);}  


    /* default size & space */
    .container{      
      min-height: 32rem;
      padding: 1rem;
    }

    .row{
      min-height: 2rem;
      padding-top: 1rem;
      margin-bottom: 1rem;
    }

    .column{
      min-height: 1.5rem;
      margin-bottom: 1rem;
      padding-left: 1rem;
      padding-right: 1rem;
      
    }