diff --git a/chrome/content/zotero-platform/unix/overlay.css b/chrome/content/zotero-platform/unix/overlay.css
index 755a43c025..d858ce096d 100644
--- a/chrome/content/zotero-platform/unix/overlay.css
+++ b/chrome/content/zotero-platform/unix/overlay.css
@@ -9,6 +9,14 @@
 /*
  * Nav bar
  */
+toolbar[id="nav-bar"] #zotero-toolbar-main-button .toolbarbutton-icon {
+	width: 28px;
+}
+
+toolbar[id="nav-bar"] #zotero-toolbar-save-button .toolbarbutton-icon {
+	width: 30px;
+}
+
 toolbar[id="nav-bar"] #zotero-toolbar-buttons #zotero-toolbar-main-button {
 	margin-right: -1px;
 	padding: 0; /* avoid shift on :active */
diff --git a/chrome/content/zotero-platform/win/overlay.css b/chrome/content/zotero-platform/win/overlay.css
index a292230a4a..d27d45ec78 100644
--- a/chrome/content/zotero-platform/win/overlay.css
+++ b/chrome/content/zotero-platform/win/overlay.css
@@ -10,15 +10,25 @@
  * Nav bar
  */
 toolbar[id="nav-bar"] #zotero-toolbar-main-button .toolbarbutton-icon {
+	width: 30px; /* 16 + 1 + 1 + 6 + 6 */
 	padding-left: 6px !important;
 	padding-right: 6px !important;
 }
 
 toolbar[id="nav-bar"] #zotero-toolbar-save-button .toolbarbutton-icon {
+	width: 29px; /* 16 + 6 + 6 + 1 */
 	padding-left: 6px !important;
 	padding-right: 6px !important;
 }
 
+toolbar[id="nav-bar"] #zotero-toolbar-main-button-single .toolbarbutton-icon {
+	width: 32px;
+}
+
+toolbar[id="nav-bar"] #zotero-toolbar-save-button-single .toolbarbutton-icon {
+	width: 31px; /* Compensate for border on only one side */
+}
+
 toolbar[id="nav-bar"] #zotero-toolbar-buttons #zotero-toolbar-save-button > .toolbarbutton-menubutton-dropmarker .dropmarker-icon {
 	padding-left: 4px;
 	padding-right: 4px;