freeCodeCamp/guide/english/certifications/responsive-web-design/basic-css/attach-a-fallback-value-to-a-css-variable/index.md

---
title: Attach a Fallback value to a CSS Variable
---
## Attach a Fallback value to a CSS Variable

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We need to add a fallback value of ```black``` to the ```background``` property of the ```.penguin-top``` and ```.penguin-bottom``` classes.

## Solution

Add a fallback value of ```black``` to the ```background``` property of the ```.penguin-bottom``` class:

```js
  .penguin-bottom {
    top: 40%;
    left: 23.5%;  
    /* change code below */
    background: var(--pengiun-skin,black);
    /* change code above */ 
    width: 53%;
    height: 45%;
    border-radius: 70% 70% 100% 100%;
  }
```

Add a fallback value of ```black``` to the ```background``` property of the ```.penguin-top``` class:

```js
  .penguin-top {
    top: 10%;
    left: 25%;
    /* change code below */
    background: var(--pengiun-skin,black);
    /* change code above */  
    width: 50%;
    height: 45%;
    border-radius: 70% 70% 60% 60%;
  }
```