.header {
  position: fixed;
  top: 0;
  left: 50%;
  width: 100%;
  z-index: 3;
  transform: translateX(-50%);
  height: 70px;
  background-color: #fff;
  line-height: 66px;
  box-shadow: 0px 0.16rem 0.8rem #ccc;
}
.header .logo {
  float: left;
  width: 150px;
  height: 45px;
}
.header .logo img {
  height: 100%;
}
.header .nav {
  float: right;
}
.header .nav li {
  float: left;
  margin-left: 80px;
}
.header .nav li a {
  font-size: 18px;
  color: #000000;
}