Scenario: Test an application’s compatibility across various browsers (including older versions) and operating systems, specifically focusing on modern HTML5 and CSS3 features. Questions: Does the application behave consistently across all target browsers (Chrome, Firefox, Safari, Edge, IE)? Are advanced features like CSS Grid, Flexbox, and Web Components supported without layout issues or functionality breaks in older browser versions? Are media queries and responsive designs rendered properly across different screen resolutions and devices? How does the application handle deprecated features in legacy browsers, and is proper fallbacks implemented?