I have tried [heading2 id="asdf" title="Text"] and [heading2 class="asdf" title="Text"], but to no avail. I can’t edit the default stylesheet if I can’t change the class, and I was looking to change the background color for this on each page individually.
Sorry at present this shortcode does not provide the class or id argument for changing the class or id. If you give me an example of what you want to accomplish, I can help you with more information on how to style this.
My thinking is you can wrap the heading2 shortcode with a div of a certain id or class (you can just use [wrap id=”my-heading1″ class=”my-heading”] shortcode for this if you are in visual editor) and then override the default styling in custom/custom.css file or the child theme. Do you see any issue with this?