@aws-amplify/ui/dist/types/theme/components/message.d.ts

`@aws-amplify/ui` contains low-level logic & styles for stand-alone usage or re-use in framework-specific implementations.

import type { Modifiers, ComponentStyles, Elements, ColorTheme } from './utils';
export type MessageTheme<Required extends boolean = false> = ComponentStyles & Modifiers<'plain' | 'outlined' | 'filled' | ColorTheme | 'neutral', Required> & Elements<{
    [key in 'icon' | 'heading' | 'content' | 'dismiss']?: ComponentStyles;
}, Required>;