.park-header-ad { margin: 20px auto; text-align: center; clear:both;}
.park-header-unit { display: inline-block; width: 300px; height: 250px;}

@media(min-width: 768px) {
    .park-header-unit { display: block; width: 728px; height: 90px; }
}

.park-content-ad { margin: 20px auto; text-align: center; clear:both;}
.park-content-unit { display: inline-block; width: 300px; height: 250px;}

@media(min-width: 768px) {
    .park-content-unit { display: block; width: 970px; height: 250px; }
}


.park-content-b-ad { margin: 20px auto; text-align: center; clear:both;}
.park-content-b-unit { display: inline-block; width: 300px; height: 250px;}

@media(min-width: 768px) {
    .park-content-b-unit { display: block; width: 970px; height: 250px; }
}

.park-content-c-ad { margin: 20px auto; text-align: center; clear:both;}
.park-content-c-unit { display: inline-block; width: 300px; height: 250px;}

@media(min-width: 768px) {
    .park-content-c-unit { display: block; width: 336px; height: 280px; }
}