header {
  height: 70px;
  line-height: 70px;
}
header .w1200 {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
header .w1200 img {
  width: 50%;
}
header .w1200 ul {
  flex: 1;
  padding-left: 2%;
  box-sizing: border-box;
  display: flex;
  justify-content: space-between;
}
header .w1200 ul li {
  flex: 1;
  text-align: center;
  transition: all 0.5s linear;
  cursor: pointer;
}
header .w1200 ul li:hover{
    background-color: #202A7B;
}
header .w1200 ul li a {
  font-size: 16px;
  transition: all 0.5s linear;
  font-weight: bold;
  color: #989898;
}
header .w1200 ul li:hover a{
  color: #fff;
}
header .w1200 .menu {
  display: none;
}
header .nav {
  position: fixed;
  top: 70px;
  left: 0;
  z-index: 999;
  width: 100vw;
  display: none;
}
header .nav ul li {
  height: 45px;
  line-height: 45px;
  padding: 0 3%;
  box-sizing: border-box;
  background-color: #F5F6FA;
  list-style: none;
  border-bottom: 1px solid #fff;
}
header .nav ul li a {
  color: #666;
  font-size: 14px;
}
header .meng {
  width: 100vw;
  height: calc(100vh - 70px);
  background-color: #000;
  opacity: 0.6;
  position: fixed;
  top: 70px;
  left: 0;
  z-index: 99;
  display: none;
}
@media screen and (max-width: 768px) {
  header .w1200 img {
    width: 80%;
  }
  header .w1200 ul {
    display: none;
  }
  header .w1200 .menu {
    display: block;
  }
  header .w1200 .menu img {
    width: 25px;
    height: 20px;
    vertical-align: sub;
  }
  header .w1200 .menu .close {
    display: none;
  }
}