The goal of bachelor thesis is to process problematic of PostCSS and CSSnext tools, wich they are used for transformation and modularity of CSS by JavaScript with using inserted imports. These tools make easier work of front-end development and web applications, thanks to standardisation syntax and modularity they, for example, compile faster. The author of his work will focus on compare development front-end web with using these postprocessing tools with preprocessor tools (SASS, LESS) and also without using any helping tools. The practical part of bachelor thesis will create the own web application, done by using CSS postprocessors, on there will be this technology detailed and practically introduced. Next goal of work will be time diffic...