A new feature that project mode brings is the support for CSS. In project mode, adding style to forms are done by using CSS defined in the stylesheet (.css) files found in the Sources folder. Designing forms with CSS has replaced the use of 4D Toolbox stylesheets. So what happens to the 4D stylesheets during an export to project? When a binary database is exported to a project, the 4D Toolbox stylesheets are automatically added to both the "styleSheets_mac.css" and "styleSheets_window.css" style sheet files. Each toolbox stylesheet from the binary structure is defined as a CSS class in project mode.