body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}
header {
    background-color: #333;
    color: white;
    padding: 10px;
    text-align: center;
}
nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow:hidden;
    background-color: #333;
    text-align: center;
}
nav li {
    display: inline-block;
}

nav li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}
nav li a:hover {
    background-color: #111;
}

.vertical-nav {
    float: left;
    width: 20%;
    background-color: #f2f2f2;
    height: 100vh; 
    padding-top: 20px;
}
.content {
    margin-left: 20%; 
    padding: 20px;
}

nav li a:hover {
    color: red;
}