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{
   text-decoration: none;
   backface-visibility: hidden;
   color: $gray;
   cursor: pointer;
   transition: color .2s;
   &:visited{
     color: auto;
   }
   &:hover{
    text-decoration: underline;
    color: $black;
   }
 }
 
 html, body{
   width: 100%;
   color: $gray;
   font-family: "Arial", "Microsoft YaHei", "微软雅黑", sans-serif;
   font-size: 14px;
   -webkit-font-smoothing: antialiased;
 }

 .clearfix:before,
 .clearfix:after{
   content: " ";
   display: inline-block;
   height: 0;
   clear: both;
   visibility: hidden;
 }

 .none{
   display: none;
 }

 .hide{
   opacity: 0;
   pointer-events: none;
 }