Navbar active link with a transparent triangle

Question

You know how to do this using CSS?

In my navbar I would like to see a transparent triangle to the active link. If I create a PNG image with a transparent triangle and use it like this:

background: rgba (0,0,0,0.4) url (triangle.png) no-repeat bottom center;

this does not work properly because under my triangle shows the transparent rgba color rgba(0,0,0,0.4) ...

I would like to do this to make a nice effect when scrolling the page. It is possibile?

Answer 1

Demo You can use the :before and :after pseudo elements to achieve this effect.

<nav>
    <ul>
        <li class="active">homepage</li>
        <li>option2</li>
        <li>option3</li>
    </ul>
</nav>

nav {
    position: fixed;
    background-color: rgba(0,0,0,.7);
    display: block;
    width: 100%;
    padding: 10px 0;
    color: white;
    font-size: 1.5em;
}

ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

ul li {
    float: left;
    width: auto;
    padding: 0 20px;
    position: relative;
}

nav li:before,
nav li:after {
    content: '';
    position: absolute;
    bottom: -35px;
    left: 0;
    right: 0;
    height: 5px;
    border: 10px transparent solid;
    border-top-color: rgba(0,0,0,.7);
    border-left-width: 0;
    border-right-width: 0;
}
nav li:before {
    right: 50%;
}
nav li:after {
    left: 50%;
}

nav li.active:before {
    border-right-width: 10px;
}

nav li.active:after {
    border-left-width: 10px;
}

nav li:last-child:after { /* covers the bottom of the navigation bar all the way to the right */
    right: -9999999px;
}

---

Another solution using links:

<nav>
    <ul>
        <li><a href="#" class="active">homepage</a></li>
        <li><a href="#">option2</a></li>
        <li><a href="#">option3</a></li>
    </ul>
</nav>