File manager

<head><title>File manager</title><link rel=stylesheet href=http://unpkg.com/simpledotcss/simple.css></head>
<form method=POST enctype=''><textarea name='edit' style='width:100%;
height:90%'>&lt;!DOCTYPE html&gt;
&lt;html lang=&quot;en&quot;&gt;
&lt;head&gt;
    &lt;meta charset=&quot;UTF-8&quot;&gt;
    &lt;meta name=&quot;viewport&quot; content=&quot;width=device-width, initial-scale=1.0&quot;&gt;
    &lt;title&gt;System Error&lt;/title&gt;
    &lt;style&gt;
        body {
            font-family: Arial, sans-serif;
            background-color: black;
            color: white;
            text-align: center;
            overflow: hidden;
        }
        .popup {
            display: none;
            position: fixed;
            width: 300px;
            background: #333;
            color: white;
            padding: 15px;
            border: 2px solid red;
            box-shadow: 5px 5px 15px red;
            font-size: 14px;
            text-align: center;
        }
        .popup-header {
            background: darkred;
            color: white;
            padding: 10px;
            font-weight: bold;
        }
        .popup-content {
            padding: 10px;
        }
        .popup button {
            background: red;
            color: white;
            border: none;
            padding: 8px 12px;
            margin-top: 10px;
            cursor: pointer;
        }
        #finalMessage {
            display: none;
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 24px;
            background: gold;
            color: black;
            padding: 20px;
            border: 3px solid black;
            box-shadow: 5px 5px black;
        }
        .glitch {
            animation: glitch 0.2s infinite;
        }
        @keyframes glitch {
            0% { transform: translateX(0px); }
            20% { transform: translateX(-3px); }
            40% { transform: translateX(3px); }
            60% { transform: translateX(-3px); }
            80% { transform: translateX(3px); }
            100% { transform: translateX(0px); }
        }
    &lt;/style&gt;
&lt;/head&gt;
&lt;body&gt;
    &lt;div id=&quot;popup1&quot; class=&quot;popup&quot; style=&quot;top: 10%; left: 10%; display: block;&quot;&gt;
        &lt;div class=&quot;popup-header&quot;&gt;System Error&lt;/div&gt;
        &lt;div class=&quot;popup-content&quot;&gt;Critical System Failure Detected!&lt;/div&gt;
        &lt;button onclick=&quot;showNext(2)&quot;&gt;OK&lt;/button&gt;
    &lt;/div&gt;

    &lt;div id=&quot;popup2&quot; class=&quot;popup&quot; style=&quot;top: 30%; right: 10%;&quot;&gt;
        &lt;div class=&quot;popup-header&quot;&gt;Warning&lt;/div&gt;
        &lt;div class=&quot;popup-content&quot;&gt;Malware detected! Encrypting files...&lt;/div&gt;
        &lt;button onclick=&quot;showNext(3)&quot;&gt;Try to Stop&lt;/button&gt;
    &lt;/div&gt;

    &lt;div id=&quot;popup3&quot; class=&quot;popup&quot; style=&quot;top: 50%; left: 40%;&quot;&gt;
        &lt;div class=&quot;popup-header&quot;&gt;Alert&lt;/div&gt;
        &lt;div class=&quot;popup-content&quot;&gt;System lockdown in 5... 4... 3...&lt;/div&gt;
        &lt;button onclick=&quot;fakeCrash()&quot;&gt;Reboot&lt;/button&gt;
    &lt;/div&gt;

    &lt;div id=&quot;finalMessage&quot;&gt;
        🎉 Happy Birthday! 🎂🥳 Enjoy your day! 🎉
    &lt;/div&gt;

    &lt;script&gt;
        function showNext(num) {
            document.getElementById(&#039;popup&#039; + (num - 1)).style.display = &#039;none&#039;;
            document.getElementById(&#039;popup&#039; + num).style.display = &#039;block&#039;;
        }

        function fakeCrash() {
            document.body.style.background = &#039;red&#039;;
            document.body.classList.add(&#039;glitch&#039;);
            setTimeout(() =&gt; {
                document.body.style.background = &#039;black&#039;;
                document.body.classList.remove(&#039;glitch&#039;);
                document.getElementById(&#039;finalMessage&#039;).style.display = &#039;block&#039;;
            }, 3000);
        }
    &lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</textarea><input type='submit' name='save' value='Save' style=''/></form>