How can I make the Facebook (or any) feed responsive?

I can’t seem to get the custom CSS to work to make the Facebook feed size change.

(Another related issue: I set the max width in the settings to 500px, for example, and a video that was shared to the Facebook page feed showing is larger than the max, despite this setting. This has me worried that even if I were able to get the responsiveness to work, it would be ruined by this video not playing nice.)

So, here’s what I tried to use:

@media only screen and (max-width : 720px) {
.fts-simple-fb-wrapper, .fts-fb-header-wrapper, .fts-fb-load-more-wrapper, .fts-jal-fb-header, .fb-social-btn-top, .fb-social-btn-bottom, .fb-social-btn-below-description {
                max-width: 320px;
            }

.fts-fb-large-photo, .fts-jal-fb-vid-picture, .fts-jal-fb-picture, .fts-fluid-videoWrapper-html5 {
                max-width: 320px;
                float: left;
            }
}

This did nothing. I currently have the max width set to 720px, because of said aforementioned video size, but once that’s gone from the feed, I’ll probably change the max width to something smaller for mobile visitors.

Has anyone else had success with making their feeds responsive? I want a smaller feed max width for someone on mobile.

Thank you!

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