Your question is Cross-Browser Compatibility at Scale. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
How do you handle cross-browser compatibility issues in a large-scale project?
Describe your practical approach to defining browser support, detecting compatibility problems, coordinating engineering and QA, and preventing regressions. Include how you would balance coverage, delivery speed, and maintenance effort.