# Why might dark-light-choose() not work?

**URL:** <https://meta.discourse.org/t/why-might-dark-light-choose-not-work/172232>\
**Category:** Support\
**Created:** [December 4, 2020, 10:14am UTC](https://meta.discourse.org/t/why-might-dark-light-choose-not-work/172232 "2020-12-04T10:14:41Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![Nacho\_Caballero](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/nacho_caballero/32/130189_2.png) [@Nacho\_Caballero](https://meta.discourse.org/u/Nacho_Caballero)\
**Post date:** [December 5, 2020, 11:32am UTC](https://meta.discourse.org/t/why-might-dark-light-choose-not-work/172232/3 "2020-12-05T11:32:25Z")

</div>

Thank you so much, Kris. You saved me! It works perfectly 🎉

I’ve been playing around with it and the only thing I don’t understand is why variable interpolation is required with color values. For example, this doesn’t work without interpolation:

```plaintext
$ins: #7f7e7e;
:root {
  --custom-ins: $ins;
}

```

But this does:

```plaintext
$ins: #7f7e7e;
:root {
  --custom-ins: #{$ins};
}

```

Both versions work if `$ins` is assigned a variable (for example: `$ins: $dark-theme-ins` ).

What am I missing?

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_[View the full topic](https://meta.discourse.org/t/why-might-dark-light-choose-not-work/172232)._