.js--lazyload {
    position: relative;
    display: block;
    background-color: #ddd
}

    .js--lazyload:not(img) {
        height: 0;
        padding-bottom: 50%
    }

img.js--lazyload {
    width: 100%
}

.js--lazyload img {
    position: absolute;
    top: 0;
    left: 0;
    display: block;
    height: 100%;
    width: 100%;
    opacity: 1;
    transition: 150ms opacity linear
}

.js--lazyload--loading img {
    opacity: 0
}