gecko-dev/browser/base/content/highlighter.css

#highlighter-container {
  pointer-events: none;
}

#highlighter-controls {
  position: absolute;
  top: 0;
  left: 0;
}

#highlighter-veil-container {
  overflow: hidden;
}

#highlighter-veil-container:not([locked]) > .highlighter-veil,
#highlighter-veil-container:not([locked]) > #highlighter-veil-middlebox,
#highlighter-veil-container:not([locked]) > #highlighter-veil-middlebox > .highlighter-veil,
#highlighter-veil-container:not([locked]) > #highlighter-veil-middlebox > #highlighter-veil-transparentbox {
  -moz-transition-property: width, height;
  -moz-transition-duration: 0.1s;
  -moz-transition-timing-function: linear;
}

#highlighter-veil-bottombox,
#highlighter-veil-rightbox {
  -moz-box-flex: 1;
}

#highlighter-veil-middlebox:-moz-locale-dir(rtl) {
  -moz-box-direction: reverse;
}

#highlighter-close-button {
  position: absolute;
  pointer-events: auto;
  z-index: 1;
}

.inspector-breadcrumbs-button {
  direction: ltr;
}

/*
 * Node Infobar
 */

#highlighter-nodeinfobar-container {
  position: absolute;
}

#highlighter-nodeinfobar-container:not([locked]) {
  -moz-transition-property: top, left;
  -moz-transition-duration: 0.1s;
  -moz-transition-timing-function: linear;
}

#highlighter-nodeinfobar {
  display: block;
  white-space: nowrap;
  direction: ltr;
}

.highlighter-nodeinfobar-arrow {
  display: none;
}

#highlighter-nodeinfobar-container[position="top"]:not([hide-arrow]) > #highlighter-nodeinfobar-arrow-bottom {
  display: block;
}

#highlighter-nodeinfobar-container[position="bottom"]:not([hide-arrow]) > #highlighter-nodeinfobar-arrow-top {
  display: block;
}

#highlighter-nodeinfobar-container[disabled] {
  visibility: hidden;
}

#highlighter-nodeinfobar-id:empty {
  display: none;
}

#highlighter-nodeinfobar-id::before {
  content: "#";
}

.highlighter-nodeinfobar-class::before {
  content: ".";
}

#highlighter-nodeinfobar-tagname {
  text-transform: lowercase;
}