.box_map {
position: relative;
display: block;
padding-bottom: 50%;
height: 0;
overflow: hidden;
}
.box_map iframe,
.box_map object,
.box_map embed {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}


@media only screen and (max-width: 640px) {
.box_map {
position: relative;
display: block;
padding-bottom: 100%;
height: 0;
overflow: hidden;
}
}