Set up Sveltia CMS - the lightweight Git-backed CMS successor to Decap/Netlify CMS with 5x smaller bundle (300 KB), GraphQL performance, and 260+ fixed predecessor issues. Framework-agnostic for Hugo, Jekyll, 11ty, Gatsby, Astro. Use when: adding CMS to static sites, migrating from Decap/Netlify CMS, enabling non-technical editors, or troubleshooting OAuth authentication failures, YAML parse errors, CORS/COOP policy problems, content not listing issues.