Handle cross-browser issues

Users report the date picker crashes in Safari 14. Reproduce the bug in Safari on macOS, localize the offending code in date-picker.js where Intl.DateTimeFormat is used, add a feature detection fallback for the Safari behavior, test in Chrome and Firefox, and push 'fix: date picker Safari fallback' by Thursday so marketing's demo works.

Before I change the date picker to handle Safari, make the fix easy to approve: show the Safari stack trace and the Intl call suspected, propose a minimal feature-detection fallback with a short comment explaining why it's needed, and list the browsers/versions tested so the reviewer can focus on the compatibility risk rather than re-reading the code.

The date picker works in Chrome but throws in Safari 14. I suspect Intl.DateTimeFormat differences but I'm unsure which behavior to rely on. I am the release owner for the demo and can't delay. Which quick diagnostic confirms whether Intl is the issue, and what is the safest fallback to implement instantly that won't break Firefox or Edge?

We keep shipping features that work in Chrome but fail in other browsers, causing late QA fire-drills. Root causes seem to be missing cross-browser testing, implicit reliance on modern APIs, and no feature-detection patterns. Which single process change will reduce these late failures the most: adding a Safari VM to CI, requiring feature detection for all new APIs, or a compatibility checklist during PR? Which is fastest to adopt for our small team?