JSFiddle - React, Tailwind, and code Playground

HTML

<div id="headerpos">
    <header>
        <nav>
            <ul>
                <li>Uvod</li>
                <li>O mne</li>
                <li>Predstaveni</li>
                <li>Galerie</li>
                <li>Videa</li>
                <li>Odkazy</li>
                <li>Kontakt</li>
            </ul>
        </nav>
    </header>
    </div>
    <div id="articlepos">
    <article>
        <header>
            <h1>Vitejte!</h1>
        </header>
        <section>

        </section>
    </article>
    </div>

CSS

body {
    background: url(images/background.jpg);
    background-attachment: fixed;
    background-repeat: no-repeat;
    background-size: cover;
    min-width: 960px;
}
nav ul {
    list-style-type: none;
}
nav ul li {
    transition-duration: 0.7s;
    float: left;
    background-color: white;
    color: black;
    height: 20px;
    width: 182px;
    text-align: center;
}
nav ul li:hover {
    background-color: black;
    color: white;
}
article {
    width: 960px;
}
#headerpos {
    position: fixed;
    right: 0;
    left: 0;
    top: 0;
    margin-top: -16px;
    margin-left: -40px;
    margin-right: -20px;
}
#articlepos {
    position: absolute;
    left: 650px;
}