#left-column {
    width: auto;
    min-width: 300px;
    max-width: 1400px;
    display: inline-block;
}

@media screen and (max-width: 900px) {
    #left-column {
        width: 100%;
        margin-left: -5%;
        display: inline-block; 
        line-height: 50px;
    }
}