import '@mui/material/styles'; declare module '@mui/material/styles' { interface TypeBackground { surface: string; } interface Palette { border: { main: string; subtle: string; }; other: { positive: string; danger: string; unread: string; }; } interface PaletteOptions { border?: { main?: string; subtle?: string; }; other?: { positive?: string; danger?: string; unread?: string; }; } }