Helpers can be styles using any standard CSS property since they are rendered as HTML elements.

Using class and style fields

Standard class and style HTML fields can be used as usual, since they won’t be treated as helper fields:

<fl-helper name="accordion" class="my-awesome-helper"></fl-helper>

The template shorthand syntax also supports both properties:

{! start welcome class="my-awesome-helper" !}
  <p>Hi {! firstName !} {! fields.lastName !}, how are you?</p>
{! end welcome !}