[ddiaz006]

Summary

Refreshes the look of the documentation site and adds a section about the CMS skills marketplace.

Preview: https://cms-ml.github.io/documentation/modernize-ui/index.html

Design

• CMS color palette (CERN blue with an orange accent) in light and dark mode, with a navy header. Before, Material's stock indigo was overriding the custom colors.
• New home page: a hero with a short intro and buttons, cards for the main sections in a 3-column grid, the newsletter banner, and the "about this site" text.
• Content pages: stronger headings, rounded tables and code blocks, a wider but capped page width, and Inter / JetBrains Mono fonts.
• The announcement bar now covers the marketplace launch and newsletter v3.

Skills marketplace

• New Skills Marketplace tab with two pages:
  • Overview: what the marketplace is, the plugins and skills, install steps (Claude Code, terminal, other agents), one-time cmslpc setup, example requests, and how skills are validated.
  • Contributing: ways to help, the PR steps, how to write a skill or subagent, the validation requirement, and a pre-PR checklist. It also suggests turning this site's inference pages into skills for the planned cms-ml plugin.
• A spotlight on the home page with the install commands, plus links from the hero and the announcement bar.
• The plugin list is labeled "Current as of November 2026" and links to the marketplace README for the live list.

Other changes

• README: install dependencies with pip install -r requirements.txt.
• Git LFS: 17 images and PDFs had been committed as regular files even though .gitattributes routes them through LFS (2 from Update feature importance section #88, 15 older). They are now stored in LFS. File contents are unchanged.
• Branch preview workflow (deploy_preview.yml): builds pushes to modernize-ui and deploys them to gh-pages/modernize-ui/. It only runs for that branch, so it does nothing after merge. It can be removed or generalized later, and the modernize-ui/ folder on gh-pages can be deleted after merge.

Testing

• mkdocs build --strict passes.
• Checked the home, marketplace and content pages in light and dark mode and at phone width.