2026-02-05: SRI Integrity Hashes Must Be Verified

Mistake: Used fabricated SRI integrity hashes for Bootstrap 5.3.3 CDN links. The browser downloaded the files (200 OK) but silently refused to apply them because the hash didn’t match, breaking all Bootstrap styling.

Rule: NEVER include integrity attributes with unverified hashes. Either:

1. Omit integrity/crossorigin attributes entirely (safe for CDN usage), or
2. Generate hashes from the actual files using openssl dgst -sha384 -binary | openssl base64 -A, or
3. Copy exact CDN tags from the official project documentation

Detection: Test that a BS5-only class (like visually-hidden) applies correct styles. If it doesn’t, the CSS isn’t being loaded.