Where does that purple gradient come from?

I've been doing LLM assisted coding for a solid year now, mostly using Cursor. Recently, I've started incorporating Claude Code into my projects as well - the mobile app is great for when you're on the go.

I'm late to adopting CLAUDE.md, SKILL.md, and similar agent instruction files, primarily because I've been getting very good results without them. However, I've been exploring skills.sh as a way to discover popular skills - it's a leaderboard of skills built by Vercel. As they describe it:

"Skills are reusable capabilities for AI agents. Install them with a single command to enhance your agents with access to procedural knowledge."

One of the most popular skills comes from Anthropic - the frontend-design skill.

Something that particularly stood out to me in the instructions:

"NEVER use generic AI-generated aesthetics like overused font families (Inter, Roboto, Arial, system fonts), cliched color schemes (particularly purple gradients on white backgrounds), predictable layouts and component patterns, and cookie-cutter design that lacks context-specific character."

Where does that purple gradient come from?

So of course, I asked Claude. Here's what it thinks