[Share] Show Number before Navigation Items

To show a number before Navigation like this

You can use this code to Custom CSS box

div.header-nav-item, div.container.header-menu-nav-item {
    counter-increment: nav;
}
div.header-nav-item>a:before, div.container.header-menu-nav-item div:before {
     content: '0' counter(nav) '.';
    position: relative;
    font-size: 20px;
}