--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -1817,29 +1817,49 @@ richlistitem[type~="action"][actiontype=
 .tabs-newtab-button,
 #TabsToolbar > #new-tab-button ,
 #TabsToolbar > #wrapper-new-tab-button > #new-tab-button {
   list-style-image: url("moz-icon://stock/gtk-add?size=menu");
   -moz-image-region: auto;
 }
 
 /* Tabbrowser arrowscrollbox arrows */
+.tabbrowser-arrowscrollbox > .scrollbutton-up > .toolbarbutton-icon,
+.tabbrowser-arrowscrollbox > .scrollbutton-down > .toolbarbutton-icon {
+  -moz-appearance: none;
+}
+
 .tabbrowser-arrowscrollbox > .scrollbutton-up,
 .tabbrowser-arrowscrollbox > .scrollbutton-down {
   -moz-appearance: none;
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-arrow-left.png");
   margin: 0 0 @tabToolbarNavbarOverlap@;
 }
 
+#TabsToolbar[brighttext] > #tabbrowser-tabs > .tabbrowser-arrowscrollbox > .scrollbutton-up,
+#TabsToolbar[brighttext] > #tabbrowser-tabs > .tabbrowser-arrowscrollbox > .scrollbutton-down {
+  list-style-image: url(chrome://browser/skin/tabbrowser/tab-arrow-left-inverted.png);
+}
+
+.tabbrowser-arrowscrollbox > .scrollbutton-up[disabled],
+.tabbrowser-arrowscrollbox > .scrollbutton-down[disabled] {
+  opacity: .4;
+}
+
+.tabbrowser-arrowscrollbox > .scrollbutton-up:-moz-locale-dir(rtl),
+.tabbrowser-arrowscrollbox > .scrollbutton-down:-moz-locale-dir(ltr) {
+  transform: scaleX(-1);
+}
+
 .tabbrowser-arrowscrollbox > .scrollbutton-down {
-  transition: 1s box-shadow ease-out;
-  border-radius: 4px;
+  transition: 1s background-color ease-out;
 }
 
 .tabbrowser-arrowscrollbox > .scrollbutton-down[notifybgtab] {
-  box-shadow: 0 0 5px 5px Highlight inset;
+  background-color: Highlight;
   transition: none;
 }
 
 #TabsToolbar .toolbarbutton-1 {
   margin-bottom: @tabToolbarNavbarOverlap@;
 }
 
 #TabsToolbar .toolbarbutton-1 > .toolbarbutton-icon,

--- a/browser/themes/linux/jar.mn
+++ b/browser/themes/linux/jar.mn
@@ -158,16 +158,18 @@ browser.jar:
   skin/classic/browser/social/share-button.png        (social/share-button.png)
   skin/classic/browser/social/share-button-active.png (social/share-button-active.png)
   skin/classic/browser/social/chat-icons.png          (social/chat-icons.png)
   skin/classic/browser/social/gear_default.png        (../shared/social/gear_default.png)
   skin/classic/browser/social/gear_clicked.png        (../shared/social/gear_clicked.png)
   skin/classic/browser/tabbrowser/connecting.png      (tabbrowser/connecting.png)
   skin/classic/browser/tabbrowser/loading.png         (tabbrowser/loading.png)
   skin/classic/browser/tabbrowser/tab-active-middle.png     (tabbrowser/tab-active-middle.png)
+  skin/classic/browser/tabbrowser/tab-arrow-left.png        (tabbrowser/tab-arrow-left.png)
+  skin/classic/browser/tabbrowser/tab-arrow-left-inverted.png (tabbrowser/tab-arrow-left-inverted.png)
   skin/classic/browser/tabbrowser/tab-background-end.png    (tabbrowser/tab-background-end.png)
   skin/classic/browser/tabbrowser/tab-background-middle.png (tabbrowser/tab-background-middle.png)
   skin/classic/browser/tabbrowser/tab-background-start.png  (tabbrowser/tab-background-start.png)
   skin/classic/browser/tabbrowser/tab-overflow-indicator.png (../shared/tabbrowser/tab-overflow-indicator.png)
 
 # NOTE: The following two files (tab-selected-end.svg, tab-selected-start.svg) get pre-processed in
 #       Makefile.in with a non-default marker of "%" and the result of that gets packaged.
   skin/classic/browser/tabbrowser/tab-selected-end.svg      (tab-selected-end.svg)

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