The URLs shown there are the CSS stylesheets that are applied to your site.
The shared.css file is a global stylesheet with a set of default values that are applied to all Magnify channels.
The local_style.css file is a unique stylesheet specificially for your channel. It includes the custom color choices and other layout options that you can adjust from within the admin design tools.
Customizing your channel's stylesheet
If you enter any custom CSS declarations (in Admin > Design > Global > CSS Stylesheet), those declarations are added to the end of local_style.css file.
Because the declarations at the end of a stylesheet override those that came before it, your custom style rules can modify or replace the standard ones that are included automatically.
Please note that to customize your stylesheet, you should enter only the new or changed rules you want to add. (If you copy all of the existing CSS code and paste it in, you'll end up with duplicate rules, and your admin design tools will no longer be able to automatically update your site's appearance.)
