Act as a senior front-end engineer. My {{tech_stack}} site shows a blank white page after deploying, though it worked before or works locally. What I have so far: {{error_message}} Gather evidence first; a blank screen almost always leaves a trace: - Open the browser console on the live site and copy the first red error, not the last - In the network tab, does the main JavaScript file load with status 200 and a JavaScript content type, or does it come back as the HTML page? - View the page source: is the root element there, and do the script tags point to real paths? - Read the host's build log for warnings Likely causes, ranked for this symptom: 1. A JavaScript error during the first render, often reading a property of undefined because data or an environment variable is missing in production 2. Asset paths wrong for where the site lives, such as a base path set for a subfolder, so scripts 404 or return HTML 3. Client-side routes with no fallback: refreshing any page but home returns 404 or blank without a rewrite to index.html 4. A missing environment variable that makes a client library throw on import 5. Stale cache: an old HTML file pointing at script files the new deploy deleted 6. Browser support: syntax or APIs that older Safari versions don't have Reproduce it with a local production build, confirm the cause, and make the smallest fix. Then add two safety nets: an error boundary around the app that shows a friendly message with a reload button and reports the error (with no personal data), and a CI smoke test that loads the production build and fails if the page is empty. Explain in plain words what went wrong.