.clearfix::before {
  content: '';
  display: block;
  clear: both;
}
* {
  padding: 0px;
  margin: 0px;
  color: #3d4451;
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  font-family: Arial, 'SimHei';
}
ul {
  list-style: none;
}
a {
  color: inherit;
  text-decoration: none;
}
body {
  background-color: #efefef;
}