sidebar_bookmarks.md

1. Install the Sidebery extension
2. In Firefox, open about:support
3. Scroll down to Profile Folder and click the Show in Finder button
4. Within the gobbldygook folder that appears, open the chrome folder.
5. Open the userChrome.css file in a text editor.
6. Paste the contents of the sidebery.css file into it
7. Relaunch Firefox

sidebery.css

/* Source https://superuser.com/questions/1424478/can-i-hide-native-tabs-at-the-top-of-firefox */
/* hides the native tabs */
#TabsToolbar {
  visibility: collapse;
}

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/autohide_sidebar.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Show sidebar only when the cursor is over it  */
/* The border controlling sidebar width will be removed so you'll need to modify these values to change width */

#sidebar-box {
  --uc-sidebar-width: 40px;
  --uc-sidebar-hover-width: 210px;
  --uc-autohide-sidebar-delay: 600ms; /* Wait 0.6s before hiding sidebar */
  --uc-autohide-transition-duration: 115ms;
  --uc-autohide-transition-type: linear;
  --browser-area-z-index-sidebar: 3;
  position: relative;
  min-width: var(--uc-sidebar-width) !important;
  width: var(--uc-sidebar-width) !important;
  max-width: var(--uc-sidebar-width) !important;
  z-index: var(--browser-area-z-index-sidebar, 3);
}
#sidebar-box[positionend] {
  direction: rtl;
}
#sidebar-box[positionend] > * {
  direction: ltr;
}

#sidebar-box[positionend]:-moz-locale-dir(rtl) {
  direction: ltr;
}
#sidebar-box[positionend]:-moz-locale-dir(rtl) > * {
  direction: rtl;
}

#main-window[sizemode="fullscreen"] #sidebar-box {
  --uc-sidebar-width: 1px;
}

#sidebar-splitter {
  display: none;
}

#sidebar-header {
  overflow: hidden;
  color: var(--chrome-color, inherit) !important;
  padding-inline: 0 !important;
}

#sidebar-header::before,
#sidebar-header::after {
  content: "";
  display: flex;
  padding-left: 8px;
}

#sidebar-header,
#sidebar {
  transition: min-width var(--uc-autohide-transition-duration)
    var(--uc-autohide-transition-type) var(--uc-autohide-sidebar-delay) !important;
  min-width: var(--uc-sidebar-width) !important;
  will-change: min-width;
}
#sidebar-box:hover > #sidebar-header,
#sidebar-box:hover > #sidebar {
  min-width: var(--uc-sidebar-hover-width) !important;
  transition-delay: 0ms !important;
}

.sidebar-panel {
  background-color: transparent !important;
  color: var(--newtab-text-primary-color) !important;
}

.sidebar-panel #search-box {
  -moz-appearance: none !important;
  background-color: rgba(249, 249, 250, 0.1) !important;
  color: inherit !important;
}

/* Add sidebar divider and give it background */

#sidebar,
#sidebar-header {
  background-color: inherit !important;
  border-inline: 1px solid rgb(80, 80, 80);
  border-inline-width: 0px 1px;
}

#sidebar-box:not([positionend]) > :-moz-locale-dir(rtl),
#sidebar-box[positionend] > * {
  border-inline-width: 1px 0px;
}

/* Move statuspanel to the other side when sidebar is hovered so it doesn't get covered by sidebar */

#sidebar-box:not([positionend]):hover ~ #appcontent #statuspanel {
  inset-inline: auto 0px !important;
}
#sidebar-box:not([positionend]):hover ~ #appcontent #statuspanel-label {
  margin-inline: 0px !important;
  border-left-style: solid !important;
}