I searched all css files but could not find the css style I inserted (which works fine on the site)

You wrote: "Changes done via the theme options are stored in the WordPress database."

So after I upgrade the theme, just restoring the database will bring back all the option changes I made?

Am I right?

TIA

Kemal

All of the theme settings - including the 'Add CSS Inserts' are stored in the database in the wp-options table and theme upgrades will not effect them.

You only have to worry if you make changes to the theme code (the files in the wp-content/themes/atahualpa folder). If you change the theme code, then you will have to re add those changes after an update.

Thank you
Regards