/* Add a black background color to the top navigation */
.topnav {
background-color: #333;
overflow: hidden;
}
/* Style the links inside the navigation bar */
.topnav a {
float: left;
display: block;
color: #f2f2f2;
text-align: center;
padding: 14px 16px;
text-decoration: none;
font-size: 17px;
border-bottom: 3px solid transparent;
}
.topnav a:hover {
border-bottom: 3px solid red;
}
.topnav a.active {
border-bottom: 3px solid red;
}