Fix typo

Author: forestream

apps/landing/src/app/(detail)/docs/devup/colors/page.mdx

@@ -7,7 +7,7 @@ export const metadata = {
 You can directly pass color values to the primitive components.
 
 ```jsx
-<Box bg="#ff0000" w={25} h={25} />
+<Box bg="#FF0000" w={25} h={25} />
 ```
 
 But, when your project gets larger and more complicated, it could be better to use variables to style your project.