Untitled

test/
    server.js
    node_modules/
        ...
    public/
        client.html
        stylesheet.css

var http = require("http");
var fs = require("fs");

function send404(response){
    console.log("There was an error!")
    response.writeHead(404, {"Content-Type": "text/plain"});
    response.write("Error 404: resource not found");
    response.end();
}

var server = http.createServer(function(req, res){
    if (req.url === "/"){
        filePath = "public/client.html";
    } else {
        filePath = "public" + req.url;
    }
    var absPath = "./" + filePath;

    fs.readFile(absPath, function(err, data){
        if (err) {
            send404(res);
        } else {
            switch (req.url) {
                case "/stylesheet.css":
                    res.writeHead(200, {"content-type": "text/css"});
                default:
                    res.writeHead(200, {"content-type": "text/html"});
            }
            res.end(data);
        }
    });
}).listen(9000);

<!DOCTYPE HTML>

<html lang="en">

<head>
    <meta charset='utf-8' />
    <link rel='stylesheet' type='text/css' href='stylesheet.css'/>
    <title>Experiment test</title>
</head>

<body>

    <div id='progress_bar'><div id='progress'></div></div>

    <div id='entryId'>
        <button id='submitId'>NEXT</button>
    </div>

</body>

</html>

html,body{
    font-family: 'Arial', sans-serif;
    background-color: white;
}

button{
  height: 50px;
  width: 150px;
  font-size: 25px;
  color: white;
  border: none;
  border-radius: 5px;
  background-color: #03A7FF;
  letter-spacing: 1px;
  cursor: pointer;
}