Как сделать фиксированное меню?

<div id="page" class="site">
    <nav id="site-navigation" class="main-navigation" role="navigation">
        <div class="menu-my-primary-menu-container">
            <ul id="primary-menu" class="menu">
                <li>
                        <a href="#home">Home</a>
                </li>
                <li>
                        <a href="#home">Home 1</a>
                </li>
                <li>
                        <a href="#home">Home 3</a>
                </li>
                <li>
                        <a href="#home">Home 2</a>
                </li>
            </ul>
        </div>
    </nav>

#site-navigation {
    position: fixed;
    min-height: 50px;
    width: 100%;
    background: #853636;
    border-top: 1px solid #e1e1e1;
}