.embed-wrap {
    max-width: 100%; /* 想多大改这里 */
    margin: 0 auto; /* 居中 */
    position: relative;
    padding-top: 56.25%; /* 16:9 */
}

.embed-wrap iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100% !important;
    height: 100% !important;
}