Material UI (@mui/material) is a React component library that implements Google's Material Design, with ready-made buttons, forms, dialogs, tables, layout grids and a theming system. Use this skill to add MUI to a React or Next.js App Router project, build a brand theme with createTheme and ThemeProvider, style components with the sx prop, set up dark mode with CSS theme variables, or upgrade v5-v7 code to the current v9 API with the official codemods. Trigger phrases: "use Material UI", "set up MUI in Next.js", "MUI theme with our brand colors", "add dark mode toggle to MUI", "fix MUI InputProps error after upgrade".
