try to use position sticky header and position webkit-sticky ,the header didnt move with user when he scroll down ,i use the inline style where the tag could effect direct but didnt work
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="style.css">
<title>Document</title>
</head>
<body>
<header class="sticky" style="position: -webkit-sticky;position: sticky;border: 2px solid red;">
<h1>Aqaba First Cohort</h1>
<nav>
<a href="">link1</a>
<a href="">link2</a>
<a href="">link3</a>
<a href="">link4</a>
</nav>
</header>
<main>
<section>
<h1>
Title Heading
</h1>
<p>
title discription
</p>
<img src="https://dummyimage.com/1000x200/c7bbc7/2b3491" alt="">
</section>
<section>Lorem ipsum, dolor sit amet consectetur adipisicing elit. Cum, labore quo reiciendis atque, provident earum deleniti fuga ipsam sapiente nisi iusto amet numquam, beatae architecto id. Eius, perspiciatis rem dolore mollitia delectus maiores pariatur, optio saepe veritatis aliquam nesciunt hic nemo voluptate suscipit provident soluta sed dignissimos? Quia tempora molestiae debitis obcaecati voluptas officia nemo quam animi asperiores recusandae voluptate quos, odit ab et similique laboriosam porro iure a ratione ipsa nostrum expedita. Fugiat, iste illum. Fugit harum quo tempora at quae ipsa, ut illo perspiciatis dicta earum in hic cumque? Ea repudiandae, eos nisi perspiciatis minus provident illo expedita harum, inventore doloribus corporis alias. Dolorem ullam cumque enim, modi quasi optio in? Id nam magni excepturi tempora, iure autem enim aut vero dolor deleniti cum minima dicta repellendus sit accusantium non? Earum quia, itaque reprehenderit dicta et iste optio possimus facere obcaecati blanditiis doloremque iure ipsam, cum repellendus enim inventore, repellat nam at saepe rxpedita. Cumque id laboriosam quo temporibus incidunt rerum fugiat delectus, voluptatum odio nostrum iusto ratione sequi suscipit natus.</section>
<section></section>
</main>
<footer></footer>
</body>
</html>