I am new to Material UI and I want to explore its grid examples. However, when I tried coding the example provided below, it gave me an error saying that there was no CSS file found to load for these examples. Without including the className parameter, I can't see the outline of the GRID, which leads me to believe that the formatting options are found in these css classes.root elements. Any help would be greatly appreciated.
function App() {
return (
<div className={classes.root}> ????
<Grid container spacing={3}>
<Grid item xs={12}>