A consistent background color system for the Features Carousel needs to be defined

The `Features Carousel` uses inconsistent background colors across its slides. In light mode, the “Run” and “Share” slides render on a white background, which blends into the surrounding page and makes the carousel section difficult to visually distinguish.
The current colors appear to be selected per slide, and the design system is not obvious. My personal suggestion here is that 1st and 3rd slide have the same color while 2nd and 4th slide have the same color ( right now in dark mode, 3 slides have a purple background while 1 has blue)

If a suitable color scheme is established by the maintainers, I will be happy to work on this issue.

**Image for reference**

No Visible Boundary:

Start by locating the Features Carousel and reviewing how its slide backgrounds are currently selected in light and dark modes. Confirm the color system with maintainers before making changes; done means the carousel has an agreed, visually distinct background scheme across all slides and both modes.

Written by the indexing model from the issue text.