点击过后的超链接就不具有active和hover了，所以调换L-V-H-A(link-visited-hover-active)
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <style> a:link { color:red } a:visited { color:green } a:hover { color:blue } a:active { color:orange } </style> </head> <body> <a href="#">百度</a> </body> </html>