Where can we apply custom style for Gravity Forms?
If I change the plugin's file formsmain.css then any updates to plugin obviously reset the changes.
I want to change the default style of default fields and define new style for Custom CSS classes defined for the fields.
Which CSS file should I change or where to add in the wordpress file structure so that the changes persist even after updating the Gravity Forms plugin or Wordpress.
There are few solutions:
For example, I'm using Avada theme and I'm adding it to the Theme Options - Custom CSS field. So, if your WP theme uses Option Tree Plugin and it has a Custom CSS field you can add code there. This way, regardless of theme, WordPress, or plugin updates you'll get to keep your custom styles.
The same thing you accomplish if you use Child Theme.
Also, you might want to check out Gravity Forms Styler plugin on Code Canyon.