The JetBrains (formerly IntelliJ) from Czech Republic has offered many excellent IDEs for various website and application developers. For example, the IntelliJ IDEA has been recognized as one of the best Java developing tools in the industry.
Performance is the key to success of any websites. And as a matter of fact, the time a web browser loading a web page takes up about 80% of the total time consumed when a visitor is accessing this page. Thus, especially for the current rich media websites or web apps, speed is extremely important. In Even Faster Web Sites, you will learn how to save the valuable website loading time, so as to make your site respond to user's requests more quickly.
First of all, Responsive Web Design by Ethan Marcotte is a very good quick-start handbook (less than 300 pages) that suitable for readers who have certain CSS basics. When finish it, you will suddenly become extensive and know the responsive web design at your finger's tips from feeling very mysterious about it.