Mobile dark mode issue: Navigation menu items have low contrast on /brand page

On the /brand page, the mobile navigation menu items appear dim in dark mode and are difficult to read.

Steps to reproduce:

1. Open https://dub.co/brand on a mobile device
2. Open the navigation menu
3. Expand sections like "Product" or "Resources"

Expected behavior: Menu items should appear white or have high contrast to remain readable on a dark background.

Actual behavior: Menu items appear dim/low-contrast, reducing readability.