.ad-container.custom_ads {
    margin-bottom: 25px;
}
    .ad-container.custom_ads iframe {
        height: auto;
    }

    .ad-container.custom_ads.ad-300 {
        max-width: 100%;
    }
        .ad-container.custom_ads.ad-300 iframe {
            height: 250px;
        }

    .ad-container.custom_ads.ad-465 {
        max-width: 100%;
    }
        .ad-container.custom_ads.ad-465 iframe {
            height: 145px;
        }

@media only screen and (min-width: 64.063em) {
    .ad-container.custom_ads.ad-300 {
        max-width: 300px;
    }

    .ad-container.custom_ads.ad-465 {
        margin: 0 auto;
        max-width: 465px;
    }
}