Google OAuth is blocked when opening an HTML file directly from disk. You need to serve it over HTTP.
Quick fix — double-click start-server.bat (in the same folder), then open:
http://localhost:8080/nutrition-tracker.html
Then add http://localhost:8080 as an Authorized JavaScript Origin in your Google Cloud OAuth credential.
Powers food photo analysis, label reading, and smart search. Free tier includes 14,400 requests/day — no credit card needed.
You can also use OpenRouter or Google Gemini. Switch providers anytime in Goals → Account.
Syncs your food log to your Google Drive. Create a Web Application OAuth credential at Google Cloud Console, enable the Drive API, and add your page URL (or http://localhost for local testing) to Authorized JavaScript Origins.