Default.css changes not showing on website.

I have activated the Product Child theme on my blog. If I select any of the 'Preset Styles' everything works fine and the correct style is visible on my site.

However when I select the 'Default' style and then make changes in the Custom Styling area these changes are not reflected on my site, the default style remains unchanged.

My theme install path is correct:disappointed:public_html/wp-content/themes/product-child