diff --git a/ronalize.css b/ronalize.css
index 3c28d9ccf..194af6766 100644
--- a/ronalize.css
+++ b/ronalize.css
@@ -264,6 +264,14 @@ button:-moz-focusring,
   outline: 1px dotted ButtonText;
 }
 
+/**
+ * Remove placeholer opacity added by Firefox
+ * https://css-tricks.com/almanac/selectors/p/placeholder/#aa-firefox-placeholder-color
+ */
+::-moz-placeholder {
+  opacity: 1;
+}
+
 /**
  * Correct the padding in Firefox.
  */