为啥我的 css 不能在 localhost.3000 上应用？

Posted 2023-02-21

【中文标题】为啥我的 css 不能在 localhost.3000 上应用？

【英文标题】：Why can't my css apply on localhost.3000?为什么我的 css 不能在 localhost.3000 上应用？

【发布时间】：2021-09-05 05:34:01

【问题描述】：

我的 INDEX.CSS 无法在我的 LOCALHOST.300 上应用。我试图安装 CSS 加载器和东西，但它仍然无法正常工作，任何人都可以帮助我吗？！ 这是我的 Header.js： 从“反应”导入反应 从 'prop-types' 导入 PropTypes； 常量头 = (title) => 返回 （

            <h1>title</h1>
        </header>
            )
        
        Header.defaultProps =
          title:'Task Tracker  '  
        
        Header.propTypes=
            title:PropTypes.string.isRequired,
        
// css in js
       // const headingStyle = 
           // color:'red', 
           // backgroundColor:'blue'
       // 
export default Header

这是我的 App.js：

import React from 'react';
import "./index.css"
import Header from "./components/Header";
 function App() 
  return (
<div className="Container">
 <Header  />
</div>
 )


export default App

这是我的 index.js：

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App'; 
import * as reportWebVitals from './reportWebVitals';
require('./index.css');


ReactDOM.render(<React.StrictMode> 
    <App />
    </React.StrictMode>,
    document.getElementById('root'));

这是我的 index.css：

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400&display=swap');

* 
  box-sizing: border-box;
  margin: 0;
  padding: 0;


body 
  font-family: 'Poppins', sans-serif;


.container 
  max-width: 500px;
  margin: 30px auto;
  overflow: auto;
  min-height: 300px;
  border: 1px solid steelblue;
  padding: 30px;
  border-radius: 5px;


.header 
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;


.btn 
  display: inline-block;
  background: #000;
  color: #fff;
  border: none;
  padding: 10px 20px;
  margin: 5px;
  border-radius: 5px;
  cursor: pointer;
  text-decoration: none;
  font-size: 15px;
  font-family: inherit;


.btn:focus 
  outline: none;


.btn:active 
  transform: scale(0.98);


.btn-block 
  display: block;
  width: 100%;


.task 
  background: #f4f4f4;
  margin: 5px;
  padding: 10px 20px;
  cursor: pointer;


.task.reminder 
  border-left: 5px solid green;


.task h3 
  display: flex;
  align-items: center;
  justify-content: space-between;


.add-form 
  margin-bottom: 40px;


.form-control 
  margin: 20px 0;


.form-control label 
  display: block;


.form-control input 
  width: 100%;
  height: 40px;
  margin: 5px;
  padding: 3px 7px;
  font-size: 17px;


.form-control-check 
  display: flex;
  align-items: center;
  justify-content: space-between;


.form-control-check label 
  flex: 1;


.form-control-check input 
  flex: 2;
  height: 20px;


footer 
  margin-top: 30px;
  text-align: center;

我的 4 个文件（index.css、App.js、Header.js 和 index.js）位于我的组件文件夹中，该文件夹位于我的 src 文件夹中

这是 package.json：

  "name": "react-task-number",
  "version": "0.1.0",
  "private": true,
  "dependencies": 
    "@testing-library/jest-dom": "^5.13.0",
    "@testing-library/react": "^11.2.7",
    "@testing-library/user-event": "^12.8.3",
    "react": "^17.0.2",
    "react-build-dist": "^0.0.8",
    "react-dom": "^17.0.2",
    "react-scripts": "^1.1.5",
    "web-vitals": "^1.1.2"
  ,
  "scripts": 
    "build:dist": "react-build-dist",
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  ,
  "eslintConfig": 
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  ,
  "browserslist": 
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  ,
  "devDependencies": 
    "css-loader": "^5.2.6",
    "style-loader": "^0.19.0"
  

这是 webpack.config.js：

const path = require('path');

module.exports = 
  entry: './src/app.js',
  output: 
    filename: 'App.js',
    path: path.resolve(__dirname, 'dist')
  ,
  module: 
    rules: [
      
        test: /\.js$/,
        exclude: /node_modules/,
        use: 
          loader: 'babel-loader',
          options: 
            presets: ['@babel/preset-env']
          
        
      ,

     // Relevant bit of config for style loader and css loader:
      
        test: /\.css$/,
        // the order of `use` is important!
        use: [ loader: 'style-loader' ,  loader: 'css-loader' ],
      ,
    ]
  ,
;

这是 webpack.config.prod.js：

const path = require('path');
const merge = require('webpack-merge');
const CleanWebpackPlugin = require('clean-webpack-plugin');
const common = require('./webpack.common.js');

module.exports = merge(common, 
    entry: 'apps/index.js',
    mode: 'production',
    devtool: 'source-map',
    output: 
        path: path.resolve(__dirname, 'dist/'),
        publicPath: '/dist/',
        filename: 'bundle.js',
        libraryTarget: 'commonjs2',
    ,
    plugins: [
        new CleanWebpackPlugin(['dist/*.*']),
    ],
    externals: 
        react: 'react',
        'react-dom': 'react-dom',
    ,
);

【问题讨论】：

请修正您的代码格式，不要对我们大喊大叫。

【参考方案1】：

因为您在 JSX 中将“Container”大写，而您的 css 中的类名是小写的

【讨论】：

你能说得更具体些吗？ JSX 在哪里？对不起，我只是个初学者

哦，它有效，谢谢你！上帝保佑你！

你应该将我的答案标记为正确然后 =] 很高兴我能提供帮助