Has there been an update this weekend that stopped videos fitting the page in mobile view?

Hi,

Last week my embedded videos were working fine in desktop and mobile view. This morning, mobile view the videos are pushing all the content out of alignment. As if the embed block is suddenly too large for the page and the video is going into the right margin. Is anyone else having this problem. Nothing else on the site changed.

I tried adding this code to target the videos in CSS but it has no effect on them.

/* resize mobile video */

@media screen and (max-width:767px) {

div#block- yui_3_17_2_1_1620636019096_30 {

    width: 40%;

    margin: 0 auto;

    padding: 0;

}

}

They are embed codes from a paid YouTube account. Example code:

<iframe width="560" height="315" src="https://www.youtube.com/embed/[number]" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Any suggestions appreciated! I can't give the website because it is a client's, behind a password with proprietary info.

Thanks