You can find this section under Interface & Design > Interventions CSS Stylesheet in the IRP Admin left navigation menu.
You should maintain all Interventions CSS in this stylesheet. Any changes you make here will be reflected in any active Interventions that are offered to customers.
When you add or update CSS on this page, be sure to click the Update Interventions Stylesheet button to save your changes and for the styles to be applied.
Be aware that any styles in the main stylesheets (Website CSS Stylesheet, Trade CSS Stylesheet or Mobile CSS Stylesheet) can potentially also apply to the intervention content. If necessary, you can use the ‘Inspect Element’ feature of your web browser to check that the intervention classes in the main stylesheets are not changing the look of your intervention. If they are, include the identical classes as styles in the Interventions Stylesheet and set them to the values you desire.