This is definitely a caching issue of some kind as the CSS the was added to the KLEO Child theme still does not show on the front end (see screenshot).
You must have some kind of caching like Varnish or Redis at the server level, or a CDN, that has not been cleared.
Contact your host to see what other caching options are enabled on your site and how to clear them.
Edit: I logged back into your site and found half of the CSS I had previously added for you had been removed. I have added this again, please leave this in tact and clear your caches to see the changes.
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