body {
  min-width: 640px;
}
#main, #page {
            -webkit-flex-flow: column;
                    flex-flow: column;
           }

           #main > section, #main > nav, #main > aside {
            /* Reorganiza el orden de la pagina */
            -webkit-order: 0;
                    order: 0;
           }
          
           #main > aside, footer {
            min-height: 100px;
            max-height: 100px;
           }

           #main > header {
            min-height: 250px;
            max-height: 250px;
            
           }