.ql-editor .iframe-wrapper {
    width: 100%;
    height: 0;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    position: relative;
}

.ql-editor .iframe-wrapper .ql-video {
    position: absolute;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
}