How to make a transparent glass menu bar with CSS3

Thanks to CSS3, our design and development options have grown a lot. In this tutorial I will how you how to make a transparent glass menu bar with CSS3.

The demo can be seen below.

See the Pen Colorful glass menu concept by Creative Punch (@CreativePunch) on CodePen.

For this demo, I wanted to have a background with some variation. I used a colorful gradient for this, but you could also use a nice image. A flat color as background would not look as good with a glass menu.

I made use of a CSS reset, and prefix-free

The HTML for the glass menu bar
The CSS for our glass menu bar will be much the same as with any menu bar. We will place a nav tag, containing an u list with links.

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<nav>
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  <ul>
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    <li>
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      <a href="#">Home</a>
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    </li>
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    <li>
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      <a href="#">Blog</a>
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    <li>
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      <a href="#">About</a>
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    </li>
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    <li>
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      <a href="#">Contact</a>
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    </li>
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  </ul>
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</nav>
The CSS for the glass menu bar
The CSS for the glass menu bar is really simple, but uses a few nice CSS3 features!

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nav {
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  max-width: 960px;
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  mask-image: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, #ffffff 25%, #ffffff 75%, rgba(255, 255, 255, 0) 100%);
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  margin: 0 auto;
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  padding: 50px 0;
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}
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nav ul {
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  text-align: center;
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  background: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0.2) 25%, rgba(255, 255, 255, 0.2) 75%, rgba(255, 255, 255, 0) 100%);
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  width: 100%;
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  box-shadow: 0 0 25px rgba(0, 0, 0, 0.1), inset 0 0 1px rgba(255, 255, 255, 0.6);
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}
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nav ul li {
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  display: inline-block;
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}
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nav ul li a {
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  padding: 20px;
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  font-family: "Roboto";
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  color: rgba(0, 0, 0, 0.5);
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  text-shadow: 1px 1px 1px rgba(255, 255, 255, 0.4);
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  font-size: 25px;
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  text-decoration: none;
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  display: block;
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}
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nav ul li a:hover {
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  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1), inset 0 0 1px rgba(255, 255, 255, 0.6);
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  background: rgba(255, 255, 255, 0.1);
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  color: rgba(0, 0, 0, 0.7);
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}
Let’s look at some of this in a bit more detail.

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nav ul {
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  text-align: center;
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  background: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0.2) 25%, rgba(255, 255, 255, 0.2) 75%, rgba(255, 255, 255, 0) 100%);
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  width: 100%;
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  box-shadow: 0 0 25px rgba(0, 0, 0, 0.1), inset 0 0 1px rgba(255, 255, 255, 0.6);
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}
I styled the ul tag with a background gradient that is white and transparent. I also added a two box-shadow values, one for an outer, dark shadow and one for an inner, light edge. Sadly the box-shadow’s sides don’t fade into the background like the gradient does. Luckily we can solve this by using the mask-image property. We apply this property on the parent element (in this case the nav). We do this so that we can apply a padding to the top and bottom. If we don’t do this, our shadows will get cut off by the mask.

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nav {
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  max-width: 960px;
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  /* The mask-image gives us some extra fading. It is not necessary but without this, you can't face out the box-shadows. This clips our menu */
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  mask-image: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, #ffffff 25%, #ffffff 75%, rgba(255, 255, 255, 0) 100%);
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  margin: 0 auto;
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  /* Using padding instead of margin for the top and bottom here will keep our box-shadow visible and not affected by the mask-image */
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  padding: 50px 0;
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}
We also use the same gradient technique for the hover event, only rotated by 90 degrees like this:

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nav ul li a:hover {
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  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1), inset 0 0 1px rgba(255, 255, 255, 0.6);
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  background: rgba(255, 255, 255, 0.1);
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  color: rgba(0, 0, 0, 0.7);
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}
This adds an extra “overlay” of glass when you hover over a menu item.

That’s pretty much all there is to it! I hope this inspires you to create some beautiful glass menus.