How to loop through a custom post type using a shortcode and output each element in the loop using shortcodes

Probably you need to create a shortcode with parameters. You should have different parameters for font size, color, bold, underline or anything else. The user should insert a value for each of these parameters in the shortcode.

You can find what you need here

It is a little tricky though because you must check the user input, because you can never be sure the user will input the proper value of a parameter.