Fix grayed-out toolbar buttons

Author: nyanpasu64

css/buttons/custom_backforward_large.css

@@ -83,7 +83,7 @@
 }
 #main-window #navigator-toolbox #nav-bar :is(#back-button, #forward-button)[disabled] .toolbarbutton-icon {
   opacity: 1.0 !important;
-  filter: grayscale(75%) !important;
+  filter: unset !important;
 }
 #main-window #navigator-toolbox #nav-bar :is(#back-button, #forward-button)[disabled] {
   opacity: 1.0 !important;

css/buttons/custom_backforward_large_ff3_strata.css

@@ -19,3 +19,18 @@
 #main-window #navigator-toolbox #nav-bar #forward-button .toolbarbutton-icon {
   list-style-image: url("./../../image/bf_ff3_strata_f.png") !important;
 }
+
+/* disabled */
+#main-window:not([uidensity=compact]):not([uidensity=touch]) #navigator-toolbox #nav-bar #back-button[disabled] .toolbarbutton-icon,
+#main-window[uidensity=compact] #navigator-toolbox #nav-bar #back-button[disabled] .toolbarbutton-icon,
+#main-window[uidensity=touch] #navigator-toolbox #nav-bar #back-button[disabled] .toolbarbutton-icon,
+#main-window #navigator-toolbox #nav-bar #back-button[disabled] .toolbarbutton-icon {
+  list-style-image: url("./../../image/bf_ff3_strata_b_dis.png") !important;
+}
+
+#main-window:not([uidensity=compact]):not([uidensity=touch]) #navigator-toolbox #nav-bar #forward-button[disabled] .toolbarbutton-icon,
+#main-window[uidensity=compact] #navigator-toolbox #nav-bar #forward-button[disabled] .toolbarbutton-icon,
+#main-window[uidensity=touch] #navigator-toolbox #nav-bar #forward-button[disabled] .toolbarbutton-icon,
+#main-window #navigator-toolbox #nav-bar #forward-button[disabled] .toolbarbutton-icon {
+  list-style-image: url("./../../image/bf_ff3_strata_f_dis.png") !important;
+}

image/bf_ff3_strata_b_dis.png

@@ -357,8 +357,8 @@
 */
 
 /* @import "./css/buttons/custom_backforward_large_ff2.css"; /**/
-/* @import "./css/buttons/custom_backforward_large_ff3.css"; /**/
-/* @import "./css/buttons/custom_backforward_large_ff3_strata.css"; /**/
+/*@import "./css/buttons/custom_backforward_large_ff3.css";*/
+@import "./css/buttons/custom_backforward_large_ff3_strata.css"; /* aero */
 /* @import "./css/buttons/custom_backforward_large_ff3_strata_orange.css"; /**/
 /* @import "./css/buttons/custom_backforward_large_ff3_strata_red.css"; /**/
 /* @import "./css/buttons/custom_backforward_large_ie8.css"; /**/