My userChrome.css for Waterfox 56.2.2

@namespace "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";


/* a close button on the left of each tab */
/* https://support.mozilla.org/questions/1157451#answer-961582 */
/* https://support.mozilla.org/questions/1157451#answer-961663 */
.tabbrowser-tab .tab-close-button {
display:-moz-box!important;
-moz-box-ordinal-group: 0 !important;
margin-left: -2px !important;
margin-right: 3px !important;
}
.tabbrowser-tab .tab-throbber,
.tabbrowser-tab .tab-icon-image,
.tabbrowser-tab .tab-sharing-icon-overlay,
.tabbrowser-tab .tab-icon-overlay,
.tabbrowser-tab .tab-label-container,
.tabbrowser-tab .tab-icon-sound {
-moz-box-ordinal-group: 2 !important;
}


/* Australis Menu Button on the Left */
#PanelUI-button,
#customization-panel-container,
#customization-panelWrapper .panel-arrow,
#ctr_panelui-button,
#wrapper-ctr_panelui-button {
  -moz-box-ordinal-group: 0
}
#PanelUI-button {
  background-position: 100% 0, calc(100% - 1px) 0, calc(100% - 2px) 0;
}
#PanelUI-popup {
  margin-right: -350px!important;
}
#PanelUI-popup .panel-arrow {
  margin-right: 340px!important;
}


/* #nav-bar{-moz-box-ordinal-group:5!important} – the toolbar, a.k.a. navigation bar, not on top */
#nav-bar{
  -moz-box-ordinal-group:5!important
}


/* monospace #urlbar  */
/* https://www.reddit.com/comments/8vq7cx/-/e1q6d9g/ */
#urlbar {
  font-family: "Source Code Pro", "Anonymous Pro", "Inconsolata", "Consolas", monospace;
}


/* green padlock */
/* https://www.reddit.com/comments/8v4l1h/-/e1kxtgx/ */
#identity-box #identity-icon-labels {
  display:none
}
#identity-box:hover #identity-icon-labels {
  display:-moz-box
}
/* https://support.mozilla.org/questions/853327#answer-222153 */
/* #identity-icon-labels { display:none!important; } */
/* #identity-box:hover #identity-icon-labels { display:block!important; } */