/* Theme topnav - from yk-liu.github.io-theme-for-fork */
.topnav {
    background-color: #1a222c;
    width: 100%;
    position: sticky;
    z-index: 3;
    top: 0;
    overflow: hidden;
    transition: top 0.3s;
}
.topnav a {
    display: block;
    float: left;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 17px;
}
.topnav a:hover { background-color: #ddd; color: black; }
.topnav a.active { background-color: #4CAF50; color: white; }
.topnav .icon { float: right; }
@media (max-width: 700px) {
    .topnav a:not(:first-child) { display: none; }
    .topnav a.icon { display: block; }
}