tdarb.org > Better Box Shadows

// 843 words // 4 minute read

Better Box Shadows

Box shadow on HTML elements has been widely supported across most browsers for a while now, but I find the default options don’t allow for much visual manipulation of the shadows in general.

Let’s take a look at a default configuration of box-shadow:

.box-container {
  box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

In the example above the first property number is the origin of the x-axis, the second number is the origin of the y-axis and the third is the amount of blur.

We should also add some minimal styling to cleanup the .box-container a little bit for our example:

<div class="box-container"></div>
.box-container {
  box-shadow: 0 4px 8px rgba(0,0,0,0.3);

  /* Styles to make it less ugly */
  background: white;
  border-radius: 10px;
  border: 1px solid #eee;
  height: 200px;
  padding: 10px;
  position: relative;
  width: 250px;
}

Which would render as this:

Not bad - but we can do a lot better than this.

Please sir, I want some more (depth)

We just need to add a simple child div (or use a pseudo element if you prefer) inside our main element we want to apply the shadow to:

<div class="box-container">
  <div class="box-container-inner"></div>
</div>

Now we make our inner child element absolute and set it’s height and width dynamically to be slightly smaller than it’s parent (percentages work best for this).

Remember to set this child element behind it’s parent by adding z-index: -1.

.box-container {
  /* No box-shadow needed on this element anymore */
  /* Styles to make it less ugly */
  background: white;
  border-radius: 10px;
  border: 1px solid #eee;
  height: 200px;
  padding: 10px;
  position: relative;
  width: 250px;
}

Inner Containers

We also need to target the box-container-inner element set inside the current parent to reflect our custom shadow styling:

.box-container-inner {
  bottom: 0;
  /* The box-shadow is added here now */
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  height: 94%;
  left: 3%;
  position: absolute;
  width: 94%;
  z-index: -1;
}

Which will make the drop-shadow render with a little more realistic depth:

But wait - there’s more!

We could stop now and have a decent drop-shadow that is certainly easier on the eyes - but we can make this even better with one extra property - filter:blur();.

So your final code would look like this:

.box-container {
  /* Styles to make it less ugly */
  background: white;
  border-radius: 10px;
  border: 1px solid #eee;
  height: 200px;
  padding: 10px;
  position: relative;
  width: 250px;
}

.box-container-inner {
  bottom: 0;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  filter: blur(6px);
  height: 94%;
  left: 3%;
  position: absolute;
  width: 94%;
  z-index: -1;
}

Which renders out into a much smoother blend of a drop-shadow, creating a more realistic illusion of depth:


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