#yt-floating {
    position: fixed;
    right: 16px;
    bottom: 16px;
    width: 360px; /* iframeのwidthと合わせる */
    max-width: calc(100vw - 32px);
    z-index: 9999;
    box-shadow: 0 8px 30px rgba(0,0,0,0.25);
    background: #000;
    border-radius: 10px;
    overflow: hidden;
}

#yt-floating iframe {
    width: 100%;
    height: 202px; /* 必要に応じて変更 */
    display: block;
}