.css
#nav {
width:800px;
height:50px;
border:1px solid black;
margin:0 auto;
}
#nav ul {
padding:0;
margin:0;
background:grey;
height:50px;
box-sizing:border-box;
}
#nav ul li {
display:inline-block;
padding:0px;
margin=0;
width:200px;
height:50px;
background:#333;
box-sizing:border-box;
text-align:center;
line-height:50px;
}
#nav ul a li {
color:grey;
text-decoration:none;
font-family:Arial Narrow;
font-weight:600;
font-size:17px;
}
.html
<!DOCTYPE html>
<html lang="es">
<head>
<link rel="stylesheet" href="estilos2.css" type="text/css" />
<meta charset="utf-8"/>
<meta name="description" content="videos frame" />
<title>navegacion</title>
</head
<body>
<div id="nav">
<ul>
<a href ="#"><li>INICIO</li></a>
<a href ="#"><li>¿QUIENES SOMOS?</li></a>
<a href ="#"><li>SERVICIOS</li></a>
<a href ="#"><li>CONTACTENOS</li></a>
</ul>
</div>
</body>
</html>
