Material-ui: Default font-size of `body` is `0.875rem` when using CssBaseline

[jim-moody]

• [x] The issue is present in the latest release.
• [x] I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

After upgrading from v3 to v4 of material ui, the font size of our entire application has changed, and the default is now 0.875rem

Expected Behavior 🤔

I would expect that the default font size is 1rem

Steps to Reproduce 🕹

https://codesandbox.io/s/clever-poitras-x70t9

[oliviertassinari]

@jim-moody Thanks for the report.
It's a duplicate of #17100.

[jim-moody]

For anyone else that has this problem, I was able to add the following to the theme object as a workaround:

const theme = createMuiTheme({
  typography: {
    body2: {
      fontSize: "1rem"
    }
  }
});

[kildareflare]

For anyone else who tries the above and it does not work. You need to ensure that CssBaseline is placed after MuiThemeProvider E.g.

 <MuiThemeProvider theme={theme}>
      <CssBaseline />
 </MuiThemeProvider>