/* Column container */
.row { 
    display: flex;
    flex-flow: row no-wrap;
}

.side {
    flex: 30%;
    background-color: #f1f1f1;
    padding: 20px;
}

/* Main column */
.main {   
    flex: 80%;
    background-color: white;
    padding: 20px;
}

/* Fake image, just for this example */
.fakeimg {
    background-color: #aaa;
    padding: 20px;
}


/* Responsive layout - when the screen is less than 700px wide, make the two columns stack on top of each other instead of next to each other */
@media screen and (max-width: 900px) {
    .row .side {   
        display: none;
    }
}