CSS（Cascading Style Sheet，层叠样式表）技术是一种格式化网页的标准方式，它是HTML功能的扩展，使网页设计者能够以更有效的方式设计出更具表现力的网页效果。(CSS (Cascading Style Sheet, cascading stylesheet) technology is a standard way to format webpages. It is an extension of HTML function, enabling webpage designers to design more expressive webpage effects in a more effective way.)