CSS

In CSS, em and rem represent relative units that display the scalable and responsive results.

A combinator is a sign that explains the relationship between selectors.

CSS selectors are used to “find” (or select) the HTML elements you want to style.

发布博客时，压缩CSS和JavaScript文件的大小，能提升网页的加载速度，这里介绍使用cssnano和Terser工具来压缩。