Add responsive option

[bradgarropy]

Video services like YouTube should allow for a responsive option to be passed in, which would wrap the iframe in a div using the padding hack.

    /* facebook and youtube videos */
    .video {
        overflow: hidden;
        position: relative;
        width: 100%;
        margin: 2rem auto;
        ::after {
            padding-top: 56.25%;
            display: block;
            content: "";
        }
        iframe {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
        }
    }