引入reset.css清除默认样式

/**
 * Eric Meyer's Reset CSS v2.0 (http://meyerweb.com/eric/tools/css/reset/) * http://cssreset.com */ html, body, div, span, applet, object, iframe,h1, h2, h3, h4, h5, h6, p, blockquote, pre,a, abbr, acronym, address, big, cite, code,del, dfn, em, img, ins, kbd, q, s, samp,small, strike, strong, sub, sup, tt, var,b, u, i, center,dl, dt, dd, ol, ul, li,fieldset, form, label, legend,table, caption, tbody, tfoot, thead, tr, th, td,article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary,time, mark, audio, video{  margin: 0;  padding: 0;  border: 0;  font-size: 100%;  font: inherit;  font-weight: normal;  vertical-align: baseline;}/* HTML5 display-role reset for older browsers */article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section{  display: block;}ol, ul, li{  list-style: none;}blockquote, q{  quotes: none;}blockquote:before, blockquote:after,q:before, q:after{  content: '';  content: none;}table{  border-collapse: collapse;  border-spacing: 0;} /* custom */a{  color: #7e8c8d;  text-decoration: none;  -webkit-backface-visibility: hidden;}::-webkit-scrollbar{  width: 5px;  height: 5px;}::-webkit-scrollbar-track-piece{  background-color: rgba(0, 0, 0, 0.2);  -webkit-border-radius: 6px;}::-webkit-scrollbar-thumb:vertical{  height: 5px;  background-color: rgba(125, 125, 125, 0.7);  -webkit-border-radius: 6px;}::-webkit-scrollbar-thumb:horizontal{  width: 5px;  background-color: rgba(125, 125, 125, 0.7);  -webkit-border-radius: 6px;}html, body{  width: 100%;  font-family: "Arial", "Microsoft YaHei", "黑体", "宋体", "微软雅黑", sans-serif;}body{  line-height: 1;  -webkit-text-size-adjust: none;  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);}html{  overflow-y: scroll;} /*清除浮动*/.clearfix:before,.clearfix:after{  content: " ";  display: inline-block;  height: 0;  clear: both;  visibility: hidden;}.clearfix{  *zoom: 1;} /*隐藏*/.dn{  display: none;}
 * ```