我尝试使用Material-UI和React构建一个网站。当尝试通过Hook API使用Material-UI的样式时，它在www.example.com中在线工作codesandbox.io，但在本地运行时无法工作。border radius属性似乎没有更新，按钮或指令对象中的任何属性也没有更新

import React from 'react';
import { makeStyles } from '@material-ui/styles';
import Stepper from '@material-ui/core/Stepper';
import Step from '@material-ui/core/Step';
import StepLabel from '@material-ui/core/StepLabel';
import Button from '@material-ui/core/Button';
import Typography from '@material-ui/core/Typography';

const useStyles = makeStyles({
  root: {
    width: "100%"
  },
  button: {
    marginRight: 10,
    borderRadius: 100,
    fontSize: 20,
  },
  instructions: {
    marginTop: 2,
    marginBottom: 5
  }
});

function getSteps() {
  return ['Select campaign settings', 'Create an ad group', 'Create an ad'];
}

function getStepContent(step) {
  switch (step) {
    case 0:
      return 'Select campaign settings...';
    case 1:
      return 'What is an ad group anyways?';
    case 2:
      return 'This is the bit I really care about!';
    default:
      return 'Unknown step';
  }
}

function HorizontalLinearStepper() {
  const classes = useStyles();
  const [activeStep, setActiveStep] = React.useState(0);
  const [skipped, setSkipped] = React.useState(new Set());
  const steps = getSteps();

  function isStepOptional(step) {
    return step === 1;
  }

  function isStepSkipped(step) {
    return skipped.has(step);
  }

  function handleNext() {
    let newSkipped = skipped;
    if (isStepSkipped(activeStep)) {
      newSkipped = new Set(newSkipped.values());
      newSkipped.delete(activeStep);
    }

    setActiveStep(prevActiveStep => prevActiveStep + 1);
    setSkipped(newSkipped);
  }

  function handleBack() {
    setActiveStep(prevActiveStep => prevActiveStep - 1);
  }

  function handleSkip() {
    if (!isStepOptional(activeStep)) {
      // You probably want to guard against something like this,
      // it should never occur unless someone's actively trying to break something.
      throw new Error("You can't skip a step that isn't optional.");
    }

    setActiveStep(prevActiveStep => prevActiveStep + 1);
    setSkipped(prevSkipped => {
      const newSkipped = new Set(prevSkipped.values());
      newSkipped.add(activeStep);
      return newSkipped;
    });
  }

  function handleReset() {
    setActiveStep(0);
  }

  return (
    <div className={classes.root}>
      <Stepper activeStep={activeStep}>
        {steps.map((label, index) => {
          const stepProps = {};
          const labelProps = {};
          if (isStepOptional(index)) {
            labelProps.optional = <Typography variant="caption">Optional</Typography>;
          }
          if (isStepSkipped(index)) {
            stepProps.completed = false;
          }
          return (
            <Step key={label} {...stepProps}>
              <StepLabel {...labelProps}>{label}</StepLabel>
            </Step>
          );
        })}
      </Stepper>
      <div>
        {activeStep === steps.length ? (
          <div>
            <Typography className={classes.instructions}>
              All steps completed - you&apos;re finished
            </Typography>
            <Button onClick={handleReset} className={classes.button}>
              Reset
            </Button>
          </div>
        ) : (
          <div>
            <Typography className={classes.instructions}>{getStepContent(activeStep)}</Typography>
            <div>
              <Button disabled={activeStep === 0} onClick={handleBack} className={classes.button}>
                Back
              </Button>
              {isStepOptional(activeStep) && (
                <Button
                  variant="contained"
                  color="primary"
                  onClick={handleSkip}
                  className={classes.button}
                >
                  Skip
                </Button>
              )}
              <Button
                variant="contained"
                color="primary"
                onClick={handleNext}
                className={classes.button}
              >
                {activeStep === steps.length - 1 ? 'Finish' : 'Next'}
              </Button>
            </div>
          </div>
        )}
      </div>
    </div>
  );
}

export default HorizontalLinearStepper;

您可以在此处查看预期结果：https://98m6j7m314.codesandbox.io，其中应用borderRadius属性后按钮边框为圆形