wikis.world.css

/* tentative style for wikis.world; mainly based on https://userstyles.world/style/7548/mastodon-alt-text-indicator */

/* highlight media without alt text in posts */
:is(
  .status,
  .detailed-status
) :is(
  .audio-player__canvas,
  .media-gallery__item-gifv-thumbnail:not(:fullscreen),
  .media-gallery__item-thumbnail img,
  .video-player:not(.fullscreen) video
):is(
  :not([title]),
  [title=""]
) {
    /* add a border (outline would avoid affecting layout but isn’t visible, idk why) */
    border: #ac6600 dashed 2px; /* Yellow30 */
    /* reduce the impact of the border on the layout */
    box-sizing: border-box;
}

/* ensure the whole border is visible in multi-image galleries */
.media-gallery {
    overflow: visible;
}

Also, to match the license of the original styles, I hereby release the contents of this gist (including its history so far) under CC0 1.0 :)