Change default Text Color Material UI

Question

Where can I change the default Text Color in the Material UI Theme?

Setting primary, secondary and error works

const styles = { a: 'red', b: 'green', ... };

createMuiTheme({
    palette: {
        primary: {
          light: styles.a,
          main: styles.b,
          dark: styles.c,
          contrastText: styles.d
        },
        secondary: {
          light: styles.aa,
          main: styles.bb,
          dark: styles.cc,
          contrastText: styles.dd
        },
        error: {
          light: styles.aaa,
          main: styles.bbb,
          dark: styles.ccc,
          contrastText: styles.ddd,
        },
    ...,
    }
...,
}

Now, when I use a <Typography /> component, I can do this

<Typography
  color='primary'
  variant='h6'>
  Foo
</Typography>

That gives it the color I defined in palette.primary.main.

However, when I leave the color prop empty

<Typography
  variant='h6'>
  Foo
</Typography>

It gives the a greyish color. Where is that color defined? Where can I define additional text colors apart from primary, secondary and error?

Simply adding another key to palette is not working...

createMuiTheme({
    palette: {
        ...,
        text1: {
          light: styles.t,
          main: styles.tt,
          dark: styles.ttt,
          contrastText: styles.tttt,
        },
    ...
    }
...
}

Answer 1

It is done like this.

createMuiTheme({
    palette: {
        ...,
        text: {
          primary: styles.t,
          secondary: styles.tt,
          disabled: styles.ttt,
          hint: styles.tttt,
        },
    ...
    }
...
}

Make sure that primary is a color code, not an object. The colors can be used like so

<Typography
    color='textPrimary'> // or 'textSecondary', 'hint', 'disabled'
    Foo Bar
</Typography>