73b56cc9c4
Next.js cannot import CSS from the /public directory - it's for static assets only. Moved theme-backstage.css and theme-spotify.css from /public to /src/css and updated imports to use proper relative paths. This fixes the @next/next/no-css-tags ESLint warnings and follows Next.js best practices for CSS imports. Signed-off-by: Charles de Dreuille <charles.dedreuille@gmail.com>