<!DOCTYPE html>
<html>
    <head>
        <meta charset=utf-8>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
            }
            nav {
                width: 500px;
            }
            nav ul {
                display: flex;
                list-style: none;
            }
            nav ul li{
                flex:1 0 0%;
            }
            nav ul li:first-child{
                flex-grow:2;
            }
        </style>
    </head>
    <body>
    	 <nav>
            <ul>
                <li>home</li>
                <li>spaceships</li>
                <li>planets</li>
                <li>stars</li>
            </ul>
        </nav>
    </body>
</html>