/* Youtube 视频嵌入 */
.embed-block .embed-video-frame {
    position: relative;
    width: 100%;
    padding-top: 56.25%;
    overflow: hidden;
}
.embed-block .embed-video-frame.is-4-3 {
    padding-top: 75%; /* 4:3 */
}
.embed-block .embed-video-frame.is-21-9 {
    padding-top: 42.857%; /* 21:9 */
}
.embed-block .embed-video-frame iframe {
    position: absolute !important;
    top: 0; left: 0;
    width: 100% !important;
    height: 100% !important;
    border: 0;
}