The Custom CSS tab is required to fine-tune the style of the WordPress plugin. This tab allows you to customize the appearance of the plugin so that it fully matches the design of your site.
Note
The Custom CSS tab required the basic knowledge of the CSS.
Most plugins created by Merkulove have a wrapper and a class that is applied to this wrapper. Usually, the class matches the name of the plugin. To find out the exact name of the class, use the developer tools of your browser. Once you know the exact name of the parent class, you can start writing CSS.

The custom CSS field accepts only plain CSS code. Do not use the syntax of LESS, SASS, SCSS, or other CSS preprocessors.
Probably in some cases, you will need to interrupt the styles of WordPress or themes that you use. Use an !important
so that your CSS code has priority over theme styles.
Save Changes
Do not forget to click Save Changes after changing plugin settings. After clicking this button, the settings will be saved and applied to all pages of the website.
You may be interested in learning about other tabs in the plugin settings. Learn more about the Assignment Tab, Uninstall Tab, Status Tab, and Activation Tab.