/* identify images and videos without alt text */
.media-gallery__item-thumbnail img:not([alt]),
.audio-player__canvas:not([title]),
.video-player video:not([title]), 
.media-gallery__gifv video:not([title])
 {
    border: 4px dashed rgba(255, 0, 0, 1);
    box-sizing: border-box;
    opacity: 0.9;
    filter: blur(1px);
    background-color: #FF0;
}