html {
  height: 100%;
}
body {
  font-family: '微软雅黑', Helvetica, Arial, '宋体', sans-serif;
  color: #000;
  -webkit-backface-visibility: hidden;
  background: #ffffff;
  height: 100%;
  margin: 0 auto;
}
.clear:after {
  content: '';
  display: block;
  height: 0;
  clear: both;
}
.hide {
  display: none;
}
.show {
  display: block;
}
.invisible {
  visibility: hidden;
}
a {
  color: inherit;
}
@media screen and (max-width: 750px) {
  html {
    font-size: 40px;
  }
}
@media screen and (max-width: 640px) {
  html {
    font-size: 34px;
  }
}
@media screen and (max-width: 415px) {
  html {
    font-size: 22px;
  }
}
@media screen and (max-width: 393px) {
  html {
    font-size: 20.96px;
  }
}
@media screen and (max-width: 384px) {
  html {
    font-size: 20.48px;
  }
}
@media screen and (max-width: 375px) {
  html {
    font-size: 20px;
  }
}
@media screen and (max-width: 360px) {
  html {
    font-size: 19.2px;
  }
}
@media screen and (max-width: 320px) {
  html {
    font-size: 17px;
  }
}