diff --git a/src/wp-admin/css/install.css b/src/wp-admin/css/install.css
index 878bbd0768..336538e5b0 100644
--- a/src/wp-admin/css/install.css
+++ b/src/wp-admin/css/install.css
@@ -305,7 +305,7 @@ body.rtl,
 		display: block;
 		max-width: none;
 		box-sizing: border-box;
-		-mox-box-sizing: border-box;
+		-moz-box-sizing: border-box;
 	}
 
 }
diff --git a/src/wp-admin/css/wp-admin.css b/src/wp-admin/css/wp-admin.css
index 29bc4c97f4..15c2bd4dd9 100644
--- a/src/wp-admin/css/wp-admin.css
+++ b/src/wp-admin/css/wp-admin.css
@@ -12375,7 +12375,7 @@ li#wp-admin-bar-menu-toggle {
 		display: block;
 		max-width: none;
 		box-sizing: border-box;
-		-mox-box-sizing: border-box;
+		-moz-box-sizing: border-box;
 	}
 
 	input[type=text].small-text,
@@ -12394,7 +12394,7 @@ li#wp-admin-bar-menu-toggle {
 	#pass-strength-result {
 		width: 100%;
 		box-sizing: border-box;
-		-mox-box-sizing: border-box;
+		-moz-box-sizing: border-box;
 		padding: 8px;
 	}