Custom Styles Not Appearing in the WordPress Admin
The Custom CSS styles in Advanced Gutenberg are very useful feature for designing your WordPress site. However, some CSS properties could mess up the Gutenberg admin layout. So not all custom styled applied in the WordPress admin.
To help you use the custom styles for paragraph blocks, we've added a color to identify the style. In the image below, the blue color for this style is shown in the admin area.
To see the custom CSS styles in use for paragraph blocks, click the “Preview” button for your post. This is the frontend output of the block shown above: