ff 57 tree style tab fixes

styles.css

/* ======================================================================= */
/*                            userChrome.css                               */
/* Create file at %AppData%\Mozilla\Firefox\Profiles\<profile_name>\chrome */
/* ======================================================================= */

/* Remove horizontal tabs */
#tabbrowser-tabs {
visibility: collapse;
}

/* tab panel narrower */
#sidebar, #sidebar-header {
  min-width: 46px !important;
}

/* background for parent (needed for margin) */
#sidebar-box:not([sidebarcommand="viewBookmarksSidebar"]):not([sidebarcommand="viewHistorySidebar"]):not([sidebarcommand="viewTabsSidebar"]) {
    background-color: #333 !important;
}

/* minimize sidebar header to a stripe (except Bookmarks, History, Sync'd Tabs); appears normally on hover */
#sidebar-box:not([sidebarcommand="viewBookmarksSidebar"]):not([sidebarcommand="viewHistorySidebar"]):not([sidebarcommand="viewTabsSidebar"])
  #sidebar-header:not(:hover) {
    max-height: 5px !important;
    min-height: 5px !important;
    padding: 0 !important;
    background-color: #333 !important;
    opacity: 1 !important;
    /* non-active area at botton */
    margin-bottom: 10px !important;
}
#sidebar-box:not([sidebarcommand="viewBookmarksSidebar"]):not([sidebarcommand="viewHistorySidebar"]):not([sidebarcommand="viewTabsSidebar"])
  #sidebar-header:not(:hover) #sidebar-switcher-target {
    opacity: 0 !important;
}

#sidebar-header {
  /* darker border and background for sidebar header */
  background-color: #838689 !important;
  border-color: #333 !important;
  /* minimaze header's height */
  font-size: 1.27em !important;
  padding: 2px !important;
}

/* ============================================== */
/*                    TST styles                  */
/* Copy into "Extra style rules" at TST settings  */
/* ============================================== */

/* panel background */
:root, #background {
  background-color: #333;
}

/* unread tabs */
.tab.unread .label {
  /*color: #900;*/
  font-style: italic;
}

/* unloaded/pending/discarded tabs */
.tab.discarded .label {
  opacity: 0.65;
  /* color: #444;
  font-style: italic;*/
} 

/* tab height, color */
.tab {
  height: 27px;
  background-color: #999;
  border-color: #444;
}

.tab.active {
  background-color: #448;
  color: #000;
}

/* hover */
.tab.active:hover {
  background-color: #559!important;
}
.tab:hover {
  background-color: #bbb !important;
  color: #000;
}

/* Show scrollbar in the tab bar rightside #1362 */
:root.left #tabbar {
  direction: ltr;
}

/* hide? new tab button*/
#tabbar:not(.overflow) .after-tabs {
  display: none;
}

/* Only show tab close button on hover */
.tab:not(:hover) .closebox {
  display: none;
}

/* hide bottom scroll */
:root.left #tabbar,
#tabContextMenu,
#tabContextMenu ul {
  margin-bottom: -17px;
}

/* Add private browsing indicator per tab
.tab.private-browsing .label:before {
  content: "🕶";
}
*/