diff --git a/src/utils/css.js b/src/utils/css.js
index 3c556b23..34dddbe7 100644
--- a/src/utils/css.js
+++ b/src/utils/css.js
@@ -1,5 +1,5 @@
 // @flow
-export const upperFirst = (value: string) => value.charAt(0).toUpperCase() + value.slice(1)
+export const upperFirst = (value: string) => value.charAt(0).toUpperCase() + value.toLowerCase().slice(1)
 
 type Value = 'xs' | 'sm' | 'md' | 'lg' | 'xl' | 'center' | 'end' | 'start' | number | boolean