There is a dedicated styling reference for each product, listing every class name and theming variable with a plain description of what it styles. Each page is also written so it can be pasted into an AI assistant (Claude, ChatGPT) together with a description of the desired look, and the assistant will write the CSS: HomeRunner plugin (explorer, booking widget, checkout, calendars): https://homerunner.io/docs/css-class-reference/, Conversion Kit: https://homerunner.io/docs/conversion-kit-styling-reference/, Toolkit: https://homerunner.io/docs/toolkit-styling-reference/, AI Concierge: https://homerunner.io/docs/ai-concierge-appearance/. Custom rules go in Appearance > Customize > Additional CSS or a snippets plugin such as WPCode, so they survive plugin updates. Note that some Conversion Kit and Toolkit modules ship with protected styling so themes cannot accidentally break them; for those, the guides list the supported path (module settings, CSS variables, or adding !important to a rule). The AI Concierge is themed from its settings screen, with one supported CSS variable for the accent color.