Yes, incompatibilities are almost inevitable. A simple web page is likely to display on all browsers without problems, but the appearance may differ slightly on various browsers. A complex page or a web application may fail on some browsers if it is not properly coded and thoroughly tested. TWENTYONE is aware of the problems. We use Mobile-first responsive coding. We use CSS style sheets to ensure a robust, maintainable layout, and we test our sites on multiple browsers to be sure they work properly.