Understanding Core Web Vitals: How Zero JS Delivers Perfect 100s

Google's Core Web Vitals measure user experience across three critical thresholds: Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS).

How Zero JS Scores Perfect 100s

1. LCP < 500ms: The server outputs fully-formed HTML. The browser parses and paints the article text on the initial packet.
2. INP = 0ms: Because there are no long-running JavaScript execution tasks, the browser's main thread remains completely idle and responsive to clicks.
3. CLS = 0: Native CSS variables define fixed typography rhythm and reserved image dimensions, preventing layout jumping.

Zero JavaScript reader delivery isn't just an aesthetic choice; it is an unfair SEO advantage.

Architecture & System Visual

Figure 1: Core Web Vitals Metrics Breakdown. Rendered and served directly from local WebP storage.