You can use the Layouts CSS and JS Editor to customize the appearance of the site that you build with Toolset Layouts.
The CSS Editor lets you add your own CSS styles, allowing you both to create new styles and to override the default styles of your theme.
The CSS rules that you add will include it on your website according to your settings.
To access the Layouts CSS Editor, go to Toolset->Layouts CSS and JS and then enter your CSS rules.
Layouts loads the CSS after the theme and plugins have loaded their CSS.
Layouts will automatically create a JS file, containing this code, and include it on your website according to your settings.