we mastered JavaScript frameworks (Angular, Vue.js, React.js) and I was involved in the development of Single Page Applications during the last 4 years. I have plenty of experience in Responsive Web Development, and I am able to convert any design files to pixel-perfect web pages in a browser-compliant way. I mastered CSS Flexbox/Grid layout, and I am very familiar with UI frameworks - Bootstrap, Material UI, Semantic UI, ...