custom styles are not applying

I have followed guides on [https://www.npmjs.com/package/mui-datatables#customize-styling](url) on how to customize styles but my custom styles are not applying.

I am trying to reduce the Table Header Height

```javascript
import {createTheme, ThemeProvider} from "@material-ui/core/styles";
import {CacheProvider} from "@emotion/react";
import createCache from "@emotion/cache";

const muiCache = createCache({
"key": "mui",
"prepend": true
});

const customTheme = createTheme({
components: {
TableHead: {
styleOverrides: {
root: {
padding: "5px"
},
footer: {
border: "1px solid #000000"
}
}
}
}
})

```

Can you guys help me out, it is so important, Thanks

Start with the linked mui-datatables custom styling guide and the supplied ThemeProvider and CacheProvider example. Compare the requested TableHead overrides with the table's styling behavior, then verify that the header height changes and the footer border appears in a reproducible example.

Written by the indexing model from the issue text.