If the CSS loading method is on External files, there will be problems…
For example, in popup border-radius doesn’t change in button element or absolute position doesn’t work in icon element. These problems cannot be solved in the front end except with Regenerate CSS files.
Thank you for the login details.
Yes, I can see the issue now. The ID level style of the Popup (ID 7571) saved in your actual page CSS file (ID 3).
If the ID level style changed inside the popup, the actual page (ID 3) CSS not regenerate. You can only trigger the regenerate when resave the page (ID 3) or Regenerate all CSS.
I have recorded it in the bug tracker.
As a workaround for now, you can move the styles from the element ID level into global class, and resave the page (ID 3). This will remove the popup styles in ID 3 and the global class style will be fetched via AJAX and ensure it’s the latest one.