How do I modify the default style of material-ui?
						
							
 use the official demo directly:  https://material-ui.com/demos.
  
 
 see that the root element in it has a fixed height of 440px and want to change it to 100%, but this  test-root-2  is returned by  classes.root  after using  withStyles , not dead. It doesn"t feel good if I directly set the style of  test-root-2 . Is there any way to set it? 
 in addition, is there any introduction to the methods in  @ material-ui/core/styles ? Official documents cannot be found. There should be many ways to find them 
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 well, I see. Just modify the height of  withStyles  the first parameter  styles.root . It turns out that you don't have to care about the specific value of  classes.root  at all. 
The function of 
  withStyles  converts a js object in the form of  css-in-js  into a real css, such as: 
const styles = (theme) => ({
  testhaha: { height: 140 },
  root: { height: 840 },
})
 after being converted to css: 
.test1-testhaha-1{
    height: 140px
}
.test1-root-1{
    height: 840px
}
 ps. The  test1  prefix here can be customized, and the custom method is followed by 
.
 well, after the conversion, the  style class name  is completely different. I'm going to write JSX. How do I know what to fill in  className= "?"  in JSX? 
 the answer is:  withStyles (styles, {name:'test1'}) (Connections) ,  Connections  is the following  class object , and its constructor can receive the transformed  style class name , method: 
class Connections extends Component {
  constructor (props) {
      super(props)
      console.log('classes', props.classes) // 
  }
  render () {
    const { classes } = this.props
    return (
      <div className={classes.root}>
          <p className={classes.testhaha}>
      </div>
    )
  }
}
 above  props.classes  content will be: 
 {
   testhaha: 'test1-testhaha-1',
   root: 'test1-root-2',
 }
 
 I believe that if you see the printed content and the converted  css-in-js , you will know the relationship between them 
.