Webpack can't find module css-loader (Error: Cannot find module '.../webpack_tutorial/node_modules/css-loader/dist/cjs.js') - node.js

Question

I'm currently learning webpack with the following tutorial on YouTube: https://www.youtube.com/watch?v=MpGLUVbqoYQ&t=1337s&ab_channel=freeCodeCamp.org, i'm on minute 43.
I want that Webpack loads my css, but when I run "node start", and the error "Cannot find module css-loader" occurs, although I have it installed properly.
This is my webpack.config.js:
const path = require('path');
module.exports = {
mode: "development",
entry: "./src/index.js",
output: {
filename: "main.js",
path: path.resolve(__dirname, "dist")
},
module: {
rules: [
{
test: /\.css$/,
use: ["css-loader"]
},
],
}
}
package.json:
{
"name": "webpack_tutorial",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "webpack --config webpack.config.js"
},
"keywords": [],
"author": "",
"license": "ISC",
"dependencies": {
"webpack": "^5.9.0",
"webpack-cli": "^4.2.0"
},
"devDependencies": {
"css-loader": "^5.0.1",
"style-loader": "^2.0.0"
}
}
index.js:
import { run } from "./app/app";
import "./main.css";
import { AlertService } from "./app/alert.service";
import { ComponentService } from "./app/component.service";
const alertService = new AlertService();
const componentService = new ComponentService();
run(alertService, componentService);
Folder structure:
dist
node_modules
src
app
some other files...
index.js
main.css
package.json
webpack.config.js
Has anyone an idea why webpack is not finding this package?