feat(module): define neutral utilities (#3629)

Co-authored-by: Sébastien Chopin <atinux@gmail.com>

src/theme/select-menu.ts

@@ -5,7 +5,7 @@ import select from './select'
 export default (options: Required<ModuleOptions>) => {
   return defuFn({
     slots: {
-      input: 'border-b border-(--ui-border)',
+      input: 'border-b border-default',
       focusScope: 'flex flex-col min-h-0',
       content: (content: string) => [content, 'origin-(--reka-combobox-content-transform-origin) w-(--reka-combobox-trigger-width)']
     }