navigation.css

#upper-nav-bar {
    position: relative;
    top: 0;
    width: 100%;
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: white;
    font-size: 14px;
    box-shadow: 2px 2px 4px 1px lightgray;
    z-index: 30;
}

#upper-nav-bar li a {
    top: 0;
    float: left;
    display: inline-block;
    color: gray;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-weight: 600;
    opacity: 0.5;
    outline: none;
}

#logo {
    float: left;
    padding-left: 10px;
    padding-right: 10px;
    background-color: rgb(0, 0, 0, 0.1);
}

#bookmark-button {
    float: right;
    margin-top: 4.5px;
    margin-right: 10px;
    outline: none;
}

#bookmark-button:hover {
    opacity: 0.5;
}

#upper-nav-bar .active-tab {
    color: #D2811E;
    opacity: 1.0;
    border-bottom:4px solid #D2811E;
}

#upper-nav-bar li a:hover {
    opacity: 1.0;
}