.wp_gallery_advanced_img100 {
    width: 100%;
    height: auto;
    background-size: cover;
}
.wp_gallery_advanced_single_thumb_wrapper {
    margin-bottom: 30px;
}
.wp_gallery_advanced_flex {
    display: -webkit-box;
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
}

.wp_gallery_advanced_thumbnails {
    flex-wrap: wrap;
}

a.wp_gallery_advanced_gal_item_thumb {
    position: relative;
    /* display: inline-block; */
    /* width: 100%; */
    margin-bottom: 30px;
    overflow: hidden;
}
.gal_overflow {
    position: absolute;
    top: 100%;
    display: flex;
    width: 100%;
    height: 100%;
    justify-content: center;
    align-items: center;
    background: rgba(0, 0, 0, 0.5);
    -webkit-transition: top 0.3s ease-in-out;
    -moz-transition: top 0.3s ease-in-out;
    -o-transition: top 0.3s ease-in-out;
    transition: top 0.3s ease-in-out;
    color: #fff;
    font-size: 50px;
}
a.wp_gallery_advanced_gal_item_thumb:hover .gal_overflow {
    top: 0;
}
.wp_gallery_advanced_caption {
    position: absolute;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    width: 100%;
    padding: 10px;
    color: #fff;
}