Apologies for the inconvenience, and thank you for bringing this to our attention.
I’ve checked your website and noticed that the page contains different heading elements for different device sizes. The one you're trying to edit for mobile view is actually hidden due to responsive display settings, which is why your font size changes are not reflecting on the frontend.
To resolve this, I recommend using the backend editor tinyurl.com/22oyjjak. From there, please ensure you select the correct heading element that is visible on mobile, and then adjust the typography settings as needed.
Let me know if you need help identifying the correct element or making these changes. I'm here to assist!