add note about helper functions and modules

STYLING.md

@@ -51,7 +51,7 @@ Any array of styles associated with a single type of React element that has at l
 
 ## Inline Styles
 
-**Inline styles are forbidden.** If we run into a case where we feel it's necessary to conditionally render some styles we should create a helper function and import it into `styles.js` then pass any modifying parameters to that function e.g.
+**Inline styles are forbidden.** If we run into a case where we feel it's necessary to conditionally render some styles we should create a helper function then pass any modifying parameters to that function. Small helper functions can be written directly in `styles.js`, but larger, more complex methods should be put in their own modules and imported into `styles.js`.
 
 ```jsx
 // Bad - Do not use inline styles