Brave-ify Firefox

folder.svg

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="100%" height="100%" viewBox="0 0 67 71" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2;">
    <g transform="matrix(4.16667,0,0,4.16667,0,0)">
        <g id="Artboard1" transform="matrix(0.03125,0,0,0.03125,5.62446e-08,0)">
            <rect x="-0" y="0" width="511.999" height="512" style="fill:none;"/>
            <g transform="matrix(1,0,0,1,-0.999998,-0.000463734)">
                <g>
                    <g transform="matrix(1,0,0,1,0.999998,0)">
                        <path d="M437.333,53.334L74.667,53.334C45.283,53.286 21.423,77.068 21.375,106.453C21.371,108.844 21.528,111.232 21.846,113.601C22.602,119.443 27.951,123.566 33.794,122.81C35.217,122.626 36.588,122.157 37.825,121.43C42.531,118.692 47.89,117.277 53.334,117.334L129.281,117.334C142.987,117.372 155.164,126.089 159.617,139.051L161.43,144.896C168.77,166.623 189.121,181.271 212.054,181.333L458.667,181.333C464.261,181.338 469.755,182.809 474.603,185.6C476.241,186.555 478.104,187.055 480,187.051C485.891,187.051 490.667,182.275 490.667,176.384L490.667,106.667C490.667,77.212 466.789,53.334 437.333,53.334Z" style="fill:rgb(21,21,21);fill-rule:nonzero;"/>
                    </g>
                    <g transform="matrix(1,0,0,1,0.999998,0)">
                        <path d="M485.397,167.211C477.283,162.482 468.058,159.994 458.666,160L212.053,160C198.347,159.962 186.17,151.245 181.717,138.283L179.904,132.438C172.564,110.711 152.213,96.063 129.28,96.001L53.333,96.001C44.168,95.912 35.149,98.292 27.221,102.892C10.408,112.301 -0.005,130.066 0,149.334L0,405.334C0,434.789 23.878,458.667 53.333,458.667L458.666,458.667C488.121,458.667 511.999,434.789 511.999,405.334L511.999,213.334C512.065,194.296 501.909,176.688 485.397,167.211Z" style="fill:rgb(113,113,113);fill-rule:nonzero;"/>
                    </g>
                </g>
            </g>
        </g>
    </g>
</svg>

userChrome.css

@media (-moz-proton) {
  /* Tab Defaults */
  .tab-background {
    border-bottom-left-radius: 0px !important;
    border-bottom-right-radius: 0px !important;
    border-bottom: none !important;
  }

  /* Selected Tabs */
  .tab-background[selected=true],
  .tab-background[multiselected=true]
  {
    border: .5px solid #7B7B7B !important;
    border-bottom: none !important;
  }

  /* Tabs that aren't selected or hovered over */
  .tab-background:not([selected=true]):not([multiselected=true]):not(:hover)
  {
    border-bottom-left-radius: 0px !important;
    border-bottom-right-radius: 0px !important;
    border-bottom: none !important;
    background-color: #191919 !important;
  }

  .tabbrowser-tab:hover > .tab-stack > .tab-content > .tab-label-container
  {
    color: #FFFFFF !important;
  }

  /* Tabs that are hovered over but not selected */
  .tabbrowser-tab:hover > .tab-stack > .tab-background:not([selected=true]):not([multiselected=true])
  {
    background-color: #262626 !important;
    border: 1px solid #3B3B3B !important;
    border-bottom: none !important;
  }


  /* Tab Height */
  :root
  {
    /* fix for full screen mode */
    --tab-toolbar-navbar-overlap: 0px !important;
    --tab-min-height: 33px !important;
    --toolbarbutton-hover-background: #242424 !important;
    --toolbarbutton-active-background: #3d3d3d !important;
  }
  /* :root #tabbrowser-tabs
  {
    --tab-min-height: 40px !important;
  } */
  #TabsToolbar
  {
    height: var(--tab-min-height) !important;
    --toolbarbutton-inner-padding: none !important;
  }

  .tabbrowser-tab
  {
    min-height: 33px !important;
  }


  /* Bookmark Bar */
  #personal-bookmarks menupopup[placespopup]
  {
    appearance: none !important;
    background-color: #292A2D !important;
    color: #E2E2E2 !important;
    border-radius: 5px !important;
  }

  #personal-bookmarks menupopup menu,
  #personal-bookmarks menupopup menuitem
  {
    padding-top: 5px !important;
    padding-bottom: 5px !important;
  }

  #personal-bookmarks menupopup menu[_moz-menuactive="true"],
  #personal-bookmarks menupopup menuitem[_moz-menuactive="true"]
  {
    appearance: none !important;
    background-color: #3F4042!important
  }

  #personal-bookmarks .bookmarks-actions-menuseparator
  {
    appearance: none !important;
    background-color: #3F4042 !important;
  }

  /* Spacing between icons */
  #personal-toolbar-empty-description,
  #PersonalToolbar .toolbarbutton-1,
  toolbarbutton.bookmark-item:not(.subviewbutton)
  {
    margin: 2px !important;
    padding: 6px !important;
  }

  /* Standard folder*/
  #bookmarks-view treechildren::-moz-tree-image(container),
  #PlacesToolbarItems toolbarbutton[container="true"],
  #PlacesToolbarItems menu[container="true"] .menu-iconic-left,
  #BMB_bookmarksPopup menu[container="true"] .menu-iconic-icon,
  #bookmarksMenu menu[container="true"] .menu-iconic-icon,
  .bookmark-item[container]
  {
    list-style-image: url('folder.svg') !important;
  }

  /* for bookmarks library */
  @-moz-document url(chrome://browser/content/places/places.xhtml)
  {
    #placesView treechildren::-moz-tree-image {
      list-style-image: url('folder.svg') !important;
      width: 16px !important;
      height: 16px !important;
    }
  }

  /* by folder name in the bookmarks toolbar to make them different for example */
  .bookmark-item[container="true"] [label="folder1"]
  {
    list-style-image: url('folder.svg') !important;
  }

  /* New Tab Button */
  #tabs-newtab-button .toolbarbutton-icon
  {
    padding: 4px !important;
  }
  :root
  {
    --toolbarbutton-hover-background: #191919 !important;
  }
}