How to use createTheme to define custom H1, H2, H3 styles in MaterialCSS

Question

I have an application using NextJS and MaterialCSS and created the following theme:

import { createTheme } from '@mui/material/styles';

export const darkTheme = createTheme({
  palette: {
    mode: 'dark',
  },
  components: {
    MuiButton: {
      styleOverrides: {
        root: {
          color: 'white',
        },
      },
    },
  },
});

export const lightTheme = createTheme({
  palette: {
    mode: 'light',
  },
});

I know how to override styles for Mui components. How do I define custom styles for the <h3> elements in my theme so that I have different h3 styles on dark themes and different h3 styles on light themes?

Answer 1

const theme = createTheme({
  typography: {
    h3: {
      fontSize: 30,
    },
    subtitle1: {
      fontSize: 12,
    },
    body1: {
      fontWeight: 500,
    },
    button: {
      fontStyle: 'italic',
    },
  },
});

文档：
https://mui.com/material-ui/customization/typography/#variants