links-enhanced.css

.markdown-preview-view .internal-link.is-unresolved {
    opacity: 0.8;
  }

  /* view URL in popup - courtesy of narand */
a.external-link {
    position: relative;
  }
  
  a.external-link:before {
    position: absolute;
    padding: 0px 8px 0px 8px;
    color: var(--text-normal);
    background-color: var(--background-primary-alt);
    border-radius: 3px;
    font-size: 80%;
    display: none;
    z-index: 1000;
    top: 1.8em;
    content: attr(href)
  }
  
  a.external-link:hover:before {
    display: inline; 
  }
  
  /* view URL in bottom of screen - courtesy Moonbase59 */
  a.external-link {
    position: relative;
  }
  
  a.external-link:before {
    position: fixed;
    left: 0;
    bottom: 0;
    padding: 0 0.5em;
    color: var(--text-normal);
    background-color: var(--background-primary-alt);
    border: 1px solid var(--background-modifier-border);
    border-radius: 0 0.4em 0 0;
    font-family: var(--default-font);
    font-size: initial;
    font-style: initial;
    font-weight: initial;
    text-decoration: initial;
    display: none;
    z-index: 1000;
    content: attr(href);
  }
  
  a.external-link:hover:before {
    display: block;
    max-width: 98%;
    overflow: hidden;
    text-overflow: ellipsis;
  }