:is :not :has :where 选择器优先级

1. id 1 0 0
2. class :require :nth-of-type :root :hover :focus ... [type=text] 0 1 0
3. p ::before ::placeholder 两个字符 :: 0 0 1
4. :where +, >, ~, " ", and || no value
5. :is() :not() :has() 已括号里最大的为准
   特殊性
   
   练习
   

https://developer.mozilla.org/en-US/docs/Web/CSS/Specificity#how_is_specificity_calculated