如何在React.js中使网页上的图标居中对齐？

import React from 'react';
import './App.css';

function App() {
  return (
    <div className="container">
      <div className="icon-container">
        <i className="icon"></i>
      </div>
    </div>
  );
}

export default App;

.container {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.icon-container {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100px;
  height: 100px;
  background-color: #ccc;
}

.icon {
  font-size: 24px;
  color: #fff;
}

import React from 'react';
import './App.css';

function App() {
  return (
    <div className="container">
      <div className="icon-container">
        <i className="icon"></i>
      </div>
    </div>
  );
}

export default App;

.container {
  position: relative;
  height: 100vh;
}

.icon-container {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 100px;
  height: 100px;
  background-color: #ccc;
}

.icon {
  font-size: 24px;
  color: #fff;
}

import React from 'react';
import './App.css';

function App() {
  return (
    <div className="container">
      <div className="icon-container">
        <i className="icon"></i>
      </div>
    </div>
  );
}

export default App;

.container {
  display: grid;
  place-items: center;
  height: 100vh;
}

.icon-container {
  width: 100px;
  height: 100px;
  background-color: #ccc;
}

.icon {
  font-size: 24px;
  color: #fff;
}