CSS

A CSS rule appears correct but does not win, or unexpectedly affects descendants. How would you debug the cascade?

Debugs matched rules, cascade origin, importance, layers, specificity, source order, inheritance, and computed values.

A page repeatedly reads and writes layout during interaction and becomes slow. How would you diagnose and fix it?

Diagnoses forced synchronous layout from interleaved geometry reads and style writes, then batches work and reduces its scope.

How does the browser turn HTML and CSS into pixels, and which steps can block or repeat?

Explains DOM and CSSOM construction, style, layout, paint, and compositing as a practical performance model.

How would you choose among cookies, localStorage, sessionStorage, and IndexedDB for browser data?

Chooses browser storage by server transport, lifetime, capacity, query needs, sensitivity, synchronization, and offline behavior.

Some users receive an old HTML shell with new assets, or a new shell that requests deleted chunks after deployment. How would you diagnose and prevent it?

Diagnoses incompatible cached HTML and immutable assets across CDN, browser, service-worker, and rollout boundaries.

Frontend Engineering Foundations

Shared JavaScript, TypeScript, browser, and CSS foundations for modern frontend interviews.

A framework-neutral frontend foundation covering JavaScript semantics, TypeScript contracts, browser rendering, CSS diagnosis, storage, caching, and production deployment failures.