img.product-grid {
    width: 100%;
    max-width: 180px
}

img.product-detail {
    width: 100%;
    max-width: 525px
}

div.product-grid-box-wrap {
    float: left;
}

@media only screen and (max-device-width: 480px) {
    .product-box-top {
        width: 100%;
    }
    div.product-grid-box-wrap {
        float: left;
        width: 100%
    }

    div.product-grid-box-wrap img {
        width: 50%;
    }
}