---
id: 60b69a66b6ddb80858c51580
title: Step 10
challengeType: 0
dashedName: step-10
---
# --description--
The `z-index` property is used to create "layers" for your HTML elements. If you are familiar with image editing tools, you may have worked with layers before. This is a similar concept.
Elements with a higher `z-index` value will appear to be layered on top of elements with a lower `z-index` value. This can be combined with the positioning in the previous lesson to create unique effects.
Since the `back-wall` element will need to appear "behind" the other elements you will be creating, give the `back-wall` element a `z-index` of `-1`.
# --hints--
Your `#back-wall` selector should have the `z-index` property set to `-1`.
```js
assert(new __helpers.CSSHelp(document).getStyle('#back-wall')?.zIndex === '-1');
```
# --seed--
## --seed-contents--
```html
Picasso Painting
```
```css
body {
background-color: rgb(184, 132, 46);
}
#back-wall {
background-color: #8B4513;
width: 100%;
height: 60%;
position: absolute;
top: 0;
left: 0;
--fcc-editable-region--
--fcc-editable-region--
}
```