.columna {
  padding:30px;
  width:33%;
  height:28%;
  float:left;
  background-color:#136bcf;
  flex-flow: column;
}

.propaganda {
  padding:160px;
  width:33%;
  height:18%;
  float:left;
  background-color:#ffffff;
}

.usuario {
  padding:30px;
  width:33%;
  height:50%;
  float:left;
  background-color:#ffffff;
    flex-flow: column;
}

@media (max-width: 800px) {
  
  .propaganda,.columna,.usuario {
    width:auto;
    float:none;
  }
  
}