To fix the ‘blank’ issue, please remove the post_id and also the field_groups arguments from the options array.
Please note that the options array is not required, as the function will merge int he default values which are shown in the documentation. You only need to provide the settings you want to customize.
If you leave the post_id and field_group blank, ACF will figure out the current post and the fields to display for this post.
If you need to edit a specific post, please only provide the post_id param and leave the field_groups blank. The field_groups param is only needed when creating a new post (because ACF doesn’t know which fields to show)
There is no CSS / class arg at the moment, sorry.
Hope that helps.
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