The Style Kit styles do not seem to apply on some elements in my design
1. Make sure you have de-activated the Elementor default fonts and colors
A common oversight is that the default Elementor Fonts and colors are still enabled. You can disable these from the Elementor > Settings > General tab, by checking the "Disable Default Colors" and "Disable Default Fonts" checkboxes.
2. Make Sure that the element is clear of manual styles
Make sure that the element does not have any manually-added styles on it. For example, if the Element is a heading, make sure that it is "clean" of any styles that might override the Style Kits.
Any style on the elements, will always override the Style Kit values. Make sure you work with your Elements as "default" as possible and try to macro-manage the design from your Style Kit panel. This applies to Columns, Sections, and other Elements that can be managed by Style Kits.
Resetting the Element styles
From the right-click menu you can easily reset the styling of the individual element so that it can inherit the Style Kit values.