Stylesheet Precedence
A Partner Organization’s alternate CSS file is applied after all other Host Company styling. When conflicting styling is identified, the styling within the stylesheet with the most precedence will be used. Partner Organization Alternate CSS files always have full precedence. For more information on Stylesheets, see the topics Stylesheet Manager and Partner Organization Stylesheet And Branding
Configuration Stylesheets and Precedence
Commerce Stylesheets and Precedence