<!DOCTYPE html>
<html>
    <head>
        <meta charset=utf-8>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
                box-sizing: border-box;
            }
            nav ul {
                height: 2rem;
                list-style: none;
                display:flex;
                flex-direction: row;
                justify-content:flex-start;
                justify-content: center;
                align-items:center;
                
            }
            nav ul li {
                border: 1px solid black;
            }
            nav ul li:first-child {
                font-size: 1.2rem;
            }
        </style>
    </head>
    <body>
    	<nav>
            <ul>
                <li>home</li>
                <li>spaceships</li>
                <li>planets</li>
                <li>stars</li>
            </ul>
        </nav>
    </body>
</html>

考察弹性盒布局

我还以为最后要写align-items:baseline;没想到啊.....