"Shadow Length" (`SHLN` in CSS) is an [axis](/glossary/axis_in_variable_fonts) found in some [variable fonts](/glossary/variable_fonts) that controls the length of a shadow applied to letterforms, allowing one to add depth and dimension to a typeface.

The [Google Fonts CSS v2 API](https://developers.google.com/fonts/docs/css2) defines the axis as:

| Default: | Min: | Max: | Step: |
| --- | --- | --- | --- |
| 50 | 0 | 100 | 1 |

<figure>

![An image showing two type specimens, each with an axis slider underneath. The specimen on the left shows the effects of the axis' lowest value. The specimen on the right shows the effects of the axis' highest value.](images/thumbnail.svg)

<figcaption>A letterform from the <a href="https://github.com/EkType/Honk">Honk</a> typeface.</figcaption>
</figure>

Changes along the Shadow Length axis increase or decrease the shadow applied to each letterform. At 0%, the shadow length is zero, while at 100% the shadow reaches the maximum length defined by the typeface’s design. The default value of 50% places the shadow midway between these extremes.

The axis uses a percentage-based scale relative to each family’s design, where 0% produces no shadow and 100% applies the maximum shadow length intended by the type designer.