Lost style customizations

Hi,
if I enter on edit mode with Brizy in any page, all graphics settings (i.e., colors, font styles and sizes) change! Here how my hompage is shown, here how it changes on edit mode. It is due to the style used: the problem is the I built the website by customizing de “Brizy default” style, but, for unknown reasons, this style has been resetted! Do you have any idea about which should be the cause?

I have a backup site where this settings are maintained: is there a way to export brizy styles in order to restore the situation?

Thanks.