.header {
    text-align: center;
    padding: 32px;
    margin-bottom: 50px;
}

.row {
    display: -ms-flexbox; /* IE10 */
    display: flex;
    -ms-flex-wrap: wrap; /* IE10 */
    flex-wrap: wrap;
}

.column {
    -ms-flex: 25%; /* IE10 */
    flex: 25%;
    max-width: 25%;
    padding: 10px;
}

.column img {
    margin-top: 20px;
    vertical-align: middle;
}

#overlay:hover {
overflow:hidden;
top:0;
left:0;
opacity:0.7;
background-color:rgba(0,0,0,0.5);
-webkit-transition:all .4s ease-in-out;
transition:all .4s ease-in-out;
}

@media screen and (max-width: 800px) {
    .column {
        -ms-flex: 50%;
        flex: 50%;
        max-width: 50%;
    }
}

/* Responsive layout - makes the two columns stack on top of each other instead of next to each other */
@media screen and (max-width: 600px) {
    .column {
        -ms-flex: 100%;
        flex: 100%;
        max-width: 100%;
    }
}