如何从react- Countdown -now中设计Countdown元素的样式？

import React from 'react';
import Countdown from 'react-countdown-now';

const CountdownComponent = () => {
  const renderer = ({ hours, minutes, seconds, completed }) => {
    if (completed) {
      // 倒计时结束时的样式
      return <span>倒计时已结束</span>;
    } else {
      // 倒计时进行中的样式
      return (
        <span>
          {hours}:{minutes}:{seconds}
        </span>
      );
    }
  };

  return (
    <div className="countdown-container">
      <Countdown date={Date.now() + 60000} renderer={renderer} />
    </div>
  );
};

.countdown-container {
  font-size: 24px;
  font-weight: bold;
  color: #333;
}

const App = () => {
  return (
    <div>
      <h1>倒计时示例</h1>
      <CountdownComponent />
    </div>
  );
};