In Cascading Style Sheets, the box model is everything. The primary purpose of CSS is visual presentation (although styling for non-visual presentation is included) and the box model is the primary mechanism of layout. Also of great importance are the inline layout model and the special mechanisms that exist to handle positioning and floating of elements. The serious designer must have a firm grasp of how the box model works and familiarity with it will allow the author to understand all the various properties will interact with each other when applied.
My favorite thing about web development is the wide variety of skills it uses. Being a good developer means staying on your toes and always learning, because there are so many important skills and these are constantly changing. Here’s a checklist of 10 skills that are some of the most important for good web developers to have. These focus a bit on front-end skills, but they apply to all developers:
lists all standard CSS properties, pseudo-classes and pseudo-elements , @-rules , and selectors in the alphabetic order. It allows you to quickly access to detailed information for each of them. It not only lists the CSS1 and CSS2.1 properties but also is a CSS3 reference that links to any CSS3 property and concept standardized, or already stabilized.