hides media on twitter behind spoiler text

disable-twitter-previews.css

@namespace url(http://www.w3.org/1999/xhtml);

@-moz-document domain("twitter.com") {
    .js-media-container,
    .AdaptiveMedia {
        display: none;
    }
    .permalink-tweet .AdaptiveMedia,
    .permalink-tweet .js-media-container {
       display: block;
    }
    .AdaptiveMediaOuterContainer::before {
        content: "[media hidden]";
        color: rgba(255, 203, 203, 0.8);
    }
}