<nav>
                <ul>
                    <li><a href="index.html">Home</a></li>
                    <li><a href="produtos.html">Produtos</a></li>
                    <li><a href="contato.html">Contato</a></li>
                </ul>
            </nav>
        </div>
    </header>

CSS:

header {
background: #BBBBBB;
padding: 20px 0;

}

.caixa { position: relative; width: 940px; margin: 0 auto; }

nav { position: absolute; top: 110px; right: 0px; }

nav li { display: inline; margin: 0 0 15px; }

nav a { text-transform: uppercase; color:black; font-weight: bold; font-size: 22px; text-decoration: none; }

nav a:hover { color: #c78c19; text-decoration: underline; }