Cluster installation demo high contrast

This post-dates @lboehling's work on high contrast - probably need to adjust borders. Just adjust the border near the code block. 

<img width="835" height="541" alt="Image" src="https://github.com/user-attachments/assets/782a201a-51be-44f0-866f-f2c9a7c1dbe2" />