.row{display: flex; flex-flow: row wrap}

.column{flex:1}

.merge2{flex:2}
.merge3{flex:3}
.merge4{flex:4}
/* add more .merge classes if you need to */

.row,.merge2,.merge3,.merge4 {margin:0 8px} /* optional gutter */


.nested{padding:0 !important; margin:0 !important; border: 0 !important}