diff --git a/chrome/custom_menupopup_check_icons.css b/chrome/custom_menupopup_check_icons.css
index edb5231..7044e61 100644
--- a/chrome/custom_menupopup_check_icons.css
+++ b/chrome/custom_menupopup_check_icons.css
@@ -3,9 +3,9 @@ See the above repository for updates as well as full license text. */
 
 /* Modifies appearance of menupopup check icons to more clearly show if the item is a radio or checkbox item */
 
-menuitem[type="radio"][checked="true"] > .menu-icon{
+menuitem[type="radio"]:is([checked=""],[checked="true"]) > .menu-icon{
   content: radial-gradient(currentColor 30%, transparent 40%) !important;
 }
-menuitem[type="checkbox"][checked="true"] > .menu-icon{
+menuitem[type="checkbox"]:is([checked=""],[checked="true"]) > .menu-icon{
   content: url("chrome://global/skin/icons/check.svg") !important;
 }
diff --git a/chrome/hide_tabs_scrollbuttons.css b/chrome/hide_tabs_scrollbuttons.css
index 0878679..5ed48ee 100644
--- a/chrome/hide_tabs_scrollbuttons.css
+++ b/chrome/hide_tabs_scrollbuttons.css
@@ -39,8 +39,8 @@ spacer[part="overflow-end-indicator"]{
   order: 2;
 }
 
-#scrollbutton-down[disabled="true"] > .toolbarbutton-icon,
-#scrollbutton-up[disabled="true"] > .toolbarbutton-icon{
+#scrollbutton-down:is([disabled=""],[disabled="true"]) > .toolbarbutton-icon,
+#scrollbutton-up:is([disabled=""],[disabled="true"]) > .toolbarbutton-icon{
   opacity: 0.4;
 } 
 #scrollbutton-up,
diff --git a/chrome/iconized_content_context_menu.css b/chrome/iconized_content_context_menu.css
index 073f541..e850e5e 100644
--- a/chrome/iconized_content_context_menu.css
+++ b/chrome/iconized_content_context_menu.css
@@ -29,7 +29,7 @@ See the above repository for updates as well as full license text. */
   display: none;
 }
 #contentAreaContextMenu > menuitem[type="checkbox"][_moz-menuactive]::before,
-#contentAreaContextMenu > menuitem[type="checkbox"][checked="true"]::before{
+#contentAreaContextMenu > menuitem[type="checkbox"]:is([checked=""],[checked="true"])::before{
   background: no-repeat center left url("chrome://global/skin/icons/check.svg");
 }
 #contentAreaContextMenu > :is(.menu-iconic,.menuitem-iconic)::before{
diff --git a/chrome/iconized_places_context_menu.css b/chrome/iconized_places_context_menu.css
index 8f8b231..bfed005 100644
--- a/chrome/iconized_places_context_menu.css
+++ b/chrome/iconized_places_context_menu.css
@@ -30,7 +30,7 @@ See the above repository for updates as well as full license text. */
   display: none;
 }
 #placesContext > menuitem[type="checkbox"][_moz-menuactive]::before,
-#placesContext > menuitem[type="checkbox"][checked="true"]::before{
+#placesContext > menuitem[type="checkbox"]:is([checked=""],[checked="true"])::before{
   background: no-repeat center left url("chrome://global/skin/icons/check.svg");
 }
 #placesContext_openBookmarkContainer\:tabs::before,
diff --git a/chrome/iconized_tabs_context_menu.css b/chrome/iconized_tabs_context_menu.css
index b7922b2..04886de 100644
--- a/chrome/iconized_tabs_context_menu.css
+++ b/chrome/iconized_tabs_context_menu.css
@@ -29,7 +29,7 @@ See the above repository for updates as well as full license text. */
   display: none;
 }
 #tabContextMenu > menuitem[type="checkbox"][_moz-menuactive]::before,
-#tabContextMenu > menuitem[type="checkbox"][checked="true"]::before{
+#tabContextMenu > menuitem[type="checkbox"]:is([checked=""],[checked="true"])::before{
   background: no-repeat center left url("chrome://global/skin/icons/check.svg");
 }
 #context_openANewTab::before{