Code blocks overlap sticky project stepper on project pages

[OleksandrMB]

What is the URL where the issue is happening

https://roadmap.sh/projects/task-tracker

What browsers are you seeing the problem on?

Chrome

Describe the Bug

When scrolling down on a project page, code blocks in the content area overlap the sticky project stepper component
The stepper is missing a z-index, so elements later in the DOM paint over it

Output from browser console (if any)

No response

Participation

• I am willing to submit a pull request for this issue.