.wrap1 {
 min-height: 800px;
  
}
.header1 {
  width: 100%;
  transition: height 0.5s ease-in;
  z-index:999999999999;
   height:2.5vw;
  line-height:2.5vw;
}
.header1.fixed {
  width: 100%;
  position: fixed;
  top: 0;
  height:2.5vw;
  line-height:2.5vw;
    z-index:99999999999999;
}