@mui/material/styles/variants.d.ts

Material UI is an open-source React component library that implements Google's Material Design. It's comprehensive and can be used in production out of the box.

import { Interpolation } from '@mui/system';
import { ComponentsPropsList } from "./props.js";
export type ComponentsVariants<Theme = unknown> = { [Name in keyof ComponentsPropsList]?: Array<{
  props: Partial<ComponentsPropsList[Name]> | ((props: Partial<ComponentsPropsList[Name]> & {
    ownerState: Partial<ComponentsPropsList[Name]>;
  }) => boolean);
  style: Interpolation<{
    theme: Theme;
  }>;
}> };