import { CSSObject } from '@mui/styled-engine';
export interface ApplyStyles<K extends string> {
    (key: K, styles: CSSObject): CSSObject;
}
/**
 * A universal utility to style components with multiple color modes. Always use it from the theme object.
 * It works with:
 *  - [Basic theme](https://mui.com/material-ui/customization/dark-mode/)
 *  - [CSS theme variables](https://mui.com/material-ui/experimental-api/css-theme-variables/overview/)
 *  - Zero-runtime engine
 *
 * Tips: Use an array over object spread and place `theme.applyStyles()` last.
 *
 * ✅ [{ background: '#e5e5e5' }, theme.applyStyles('dark', { background: '#1c1c1c' })]
 *
 * 🚫 { background: '#e5e5e5', ...theme.applyStyles('dark', { background: '#1c1c1c' })}
 *
 * @example
 * 1. using with `styled`:
 * ```jsx
 *   const Component = styled('div')(({ theme }) => [
 *     { background: '#e5e5e5' },
 *     theme.applyStyles('dark', {
 *       background: '#1c1c1c',
 *       color: '#fff',
 *     }),
 *   ]);
 * ```
 *
 * @example
 * 2. using with `sx` prop:
 * ```jsx
 *   <Box sx={theme => [
 *     { background: '#e5e5e5' },
 *     theme.applyStyles('dark', {
 *        background: '#1c1c1c',
 *        color: '#fff',
 *      }),
 *     ]}
 *   />
 * ```
 *
 * @example
 * 3. theming a component:
 * ```jsx
 *   extendTheme({
 *     components: {
 *       MuiButton: {
 *         styleOverrides: {
 *           root: ({ theme }) => [
 *             { background: '#e5e5e5' },
 *             theme.applyStyles('dark', {
 *               background: '#1c1c1c',
 *               color: '#fff',
 *             }),
 *           ],
 *         },
 *       }
 *     }
 *   })
 *```
 */
export default function applyStyles<K extends string>(key: K, styles: CSSObject): CSSObject;
