The background color, corner radius, and border and thickness styles of "header" and "content" viewers are defined in class selectors of the external CSS file: "example.css" (Listing 19).

“header”和“content”查看器的背景颜色、圆角半径、边框和透明度都在外部css文件example . css的类选择器中定义(见清单19)。