declare module '@mui/material/styles' {
  interface TypeBackground {
    level1?: string;
    level2?: string;
    level3?: string;
  }

  interface PaletteBackgroundChannel {
    level1?: string;
    level2?: string;
    level3?: string;
  }

  interface Palette {
    neutral: Palette['primary'];
  }

  interface PaletteOptions {
    neutral?: PaletteOptions['primary'];
  }
}

export { }; // ✅ important