.column {
background: #93dcff;
float: left;
background-color: green;
width: 100%;
height: 200px;
}
.container .column:first-child{
margin-right: 4%;
}
@media screen and (max-width: 767px){
.column {
float: none;
background-color: red;
width: 50%;
height: 200px;
}
.container .column:first-child{
margin-right: 0;
margin-bottom: 20px;
}
}