Revert Roadmap Typography to Match BRC Design Mocks

The typography on the roadmap page was recently altered and now deviates from our approved BRC design mockups. This change introduces inconsistencies in font family, sizing, weight, and line-height, breaking the unified look-and-feel across the site.

<img width="2337" height="1094" alt="Image" src="https://github.com/user-attachments/assets/3b5cd297-7128-458b-aee0-e30234c1892f" />