404.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta
            http-equiv="Content-Security-Policy"
            content="default-src 'self' 'unsafe-inline' https: http:; img-src https: 'self'; font-src https: http: 'self'"
        />
        <title>404</title>
        <link rel="stylesheet" href="/vendors/bootstrap/bootstrap.min.css" />
        <style type="text/css" media="screen">
            .container {
                margin: 10px auto;
                max-width: 600px;
                text-align: center;
            }

            h1 {
                margin: 30px 0;
                font-size: 4em;
                line-height: 1;
                letter-spacing: -1px;
            }
        </style>
    </head>

    <body>
        <div class="container">
            <h1>404</h1>

            <p><strong>Page not found :(</strong></p>
            <p>The requested page could not be found.</p>
            <h3>
                <a href="/">Back to home</a>
            </h3>
        </div>
    </body>
</html>