Common.css

Note: After saving, you may have to bypass your browser's cache to see the changes.

Firefox / Safari: Hold Shift while clicking Reload, or press either Ctrl-F5 or Ctrl-R (⌘-R on a Mac)
Google Chrome: Press Ctrl-Shift-R (⌘-Shift-R on a Mac)
Internet Explorer / Edge: Hold Ctrl while clicking Refresh, or press Ctrl-F5
Opera: Go to Menu → Settings (Opera → Preferences on a Mac) and then to Privacy & security → Clear browsing data → Cached images and files.

/* Answer: How to add image with link in a sidebar - MediaWiki https://stackoverflow.com/a/53597787/8992875?stw=2 */
#n-recordwizard> a:after {
  content: ' ';
  background-image: url(https://upload.wikimedia.org/wikipedia/commons/1/1e/Breezeicons-status-22-mic-red-LinguaLibre.svg);
  position: absolute;
  width: 40px;
  height: 40px;
  /*left:-6px; /* :before */
  top: -3px;
  background-repeat: no-repeat;
}
#n-menu-datasets > a[href$='/datasets/'] {
    background: #a3dbd7 url(https://upload.wikimedia.org/wikipedia/commons/4/4c/Farm-Fresh_file_extension_zip.png) center right no-repeat;
    padding-right: 32px;
}
#n-recordwizard { 
    position:relative;
}