Mastodon Alt Text Indicator by cincodenada

/* ==UserStyle==
@name           Mastodon Alt Text Indicator
@namespace      github.com/openstyles/stylus
@version        1.1.1
@description    Highlights images on Mastodon with a red dotted border if they don't have alt text
@author         Ell Bradshaw
==/UserStyle== */
@-moz-document regexp(".*") {
  /* For some reason the gallery hides the outer 2px of the image edges for multi-image galleries, this makes our dotted lines visible again */
  #mastodon .media-gallery {
    overflow: visible;
    /* Alternate option: */
    /* padding: 2px; */
  }

  /* Selectors borrowed from friend.camp's custom CSS */
  #mastodon .audio-player__canvas:not([title]),
  #mastodon .audio-player__canvas[title=""],
  #mastodon .media-gallery__gifv video:not([title]),
  #mastodon .media-gallery__gifv video[title=""],
  #mastodon .media-gallery__item-thumbnail img:not([alt]),
  #mastodon .media-gallery__item-thumbnail img[alt=""],
  #mastodon .video-player video:not([title]),
  #mastodon .video-player video[title=""] {
    /* Change border width or color here if you like */
    border: 3px dashed red;
    box-sizing: border-box;
  }
}