diff --git a/chrome.manifest b/chrome.manifest
index a5ab30410..9a39da559 100644
--- a/chrome.manifest
+++ b/chrome.manifest
@@ -69,6 +69,8 @@ overlay chrome://zotero/content/preferences/preferences_advanced.xul chrome://zo
 overlay chrome://mozapps/content/downloads/unknownContentType.xul chrome://zotero/content/downloadOverlay.xul
 
 style	chrome://browser/content/browser.xul	chrome://zotero/skin/zotero.css
+style	chrome://browser/content/browser.xul	chrome://zotero/skin/zotero-fx55.css platformversion>=55
+
 style	chrome://global/content/customizeToolbar.xul	chrome://zotero/skin/zotero.css
 
 component	{e4c61080-ec2d-11da-8ad9-0800200c9a66}			components/zotero-service.js
diff --git a/chrome/content/zotero-platform/mac/overlay.css b/chrome/content/zotero-platform/mac/overlay.css
index 0067556e4..10bd317a4 100644
--- a/chrome/content/zotero-platform/mac/overlay.css
+++ b/chrome/content/zotero-platform/mac/overlay.css
@@ -76,15 +76,6 @@
 	border-left: 1px solid transparent;
 }
 
-
-/* Firefox 55 changes */
-#zotero-toolbar-buttons[cui-areatype="toolbar"]:hover .toolbarbutton-menubutton-button,
-#zotero-toolbar-buttons[cui-areatype="toolbar"]:hover .toolbarbutton-menubutton-dropmarker,
-#zotero-toolbar-save-button[cui-areatype="toolbar"]:hover > .toolbarbutton-menubutton-button,
-#zotero-toolbar-save-button[cui-areatype="toolbar"]:hover > .toolbarbutton-menubutton-dropmarker {
-	border: 0 !important;
-}
-
 /*
  * Alterations for overflow menu
  */
diff --git a/chrome/skin/default/zotero/zotero-fx55.css b/chrome/skin/default/zotero/zotero-fx55.css
new file mode 100644
index 000000000..15fe6bd3f
--- /dev/null
+++ b/chrome/skin/default/zotero/zotero-fx55.css
@@ -0,0 +1,12 @@
+#zotero-toolbar-buttons[cui-areatype="toolbar"]:hover .dropmarker-icon,
+#zotero-toolbar-save-button[cui-areatype="toolbar"]:hover .dropmarker-icon {
+       padding-top: calc(var(--toolbarbutton-inner-padding) + 5px);
+       padding-bottom: calc(var(--toolbarbutton-inner-padding) + 5px);
+}
+
+#zotero-toolbar-buttons[cui-areatype="toolbar"]:hover .toolbarbutton-menubutton-button,
+#zotero-toolbar-buttons[cui-areatype="toolbar"]:hover .toolbarbutton-menubutton-dropmarker,
+#zotero-toolbar-save-button[cui-areatype="toolbar"]:hover > .toolbarbutton-menubutton-button,
+#zotero-toolbar-save-button[cui-areatype="toolbar"]:hover > .toolbarbutton-menubutton-dropmarker {
+       border: 0 !important;
+}
diff --git a/chrome/skin/default/zotero/zotero.css b/chrome/skin/default/zotero/zotero.css
index 494c1c795..eb1b8d562 100644
--- a/chrome/skin/default/zotero/zotero.css
+++ b/chrome/skin/default/zotero/zotero.css
@@ -128,13 +128,6 @@ toolbarpaletteitem[place="palette"] #zotero-toolbar-buttons #zotero-toolbar-save
 }
 
 
-#zotero-toolbar-buttons[cui-areatype="toolbar"]:hover .dropmarker-icon,
-#zotero-toolbar-save-button[cui-areatype="toolbar"]:hover .dropmarker-icon {
-	padding-top: calc(var(--toolbarbutton-inner-padding) + 5px);
-	padding-bottom: calc(var(--toolbarbutton-inner-padding) + 5px);
-}
-
-
 /* Show webpage icon in gray when no translators */
 #zotero-toolbar-save-button:not(.translate),
 #zotero-toolbar-save-button-single:not(.translate),