Update index.md

files/en-us/learn/getting_started_with_the_web/what_will_your_website_look_like/index.md

@@ -21,7 +21,7 @@ To begin, you'll need to answer these questions:
 3. **What does your website look like,** in simple high-level terms? What's the background color? What kind of font is appropriate: formal, cartoony, bold and loud, subtle?
 
 > [!NOTE]
-> Complex projects need detailed guidelines that go into all the details of colors, fonts, spacing between items on a page, appropriate writing style, and so on. This is sometimes called a design guide, design system, or brand book, and you can see an example at the [Firefox Photon Design System](https://design.firefox.com/photon/).
+> Complex projects need detailed guidelines that go into all the details of colors, fonts, spacing between items on a page, appropriate writing style, and so on. This is sometimes called a design guide, design system, or brand book, and you can see an example at the [Firefox Acorn Design System](https://acorn.firefox.com/latest/).
 
 ## Sketching out your design