#header {
  position: fixed;
  text-align: center;
  padding: 2vh auto 3vh auto;
  padding: 0;
  width: 100%;
  height: 14vh;
  z-index: 3;
}
nav, ul{
  width: 100%;
  height: 14vh;
  margin: 0;
  padding: 0;
  top: 0;
}
ul {
  background-color: rgba(0,0,0,0.65);
}
ul li{
  display: inline;
  width: 15%;
  height: 10vh;
  float: left;
  margin-top: 2.5vh;
}
ul li:first-of-type {
  margin-left: 5%;
}
ul li a{
  font-family: "メイリオ";
  font-size: 2.5vh;
  display: block;
  width: 100%;
  padding: 2.6vh 0;
  text-decoration: none;
  color: #bbb;
  font-weight: bold;
}
ul li.current{
  border: 0.5vh solid #888;
  box-sizing: border-box;
  margin-top: 2vh;
}
ul li.current a, ul li.current a:hover{
  color: #888;
  cursor: default;
}
ul li a:hover{
  color: #fff;
}

.hamburger {
  display: none;
}

@media screen and (max-width: 920px) {
  #header, nav, ul {
    height: 0px;
  }
  .hamburger {
    display: block;
    margin-top: 21px;
    margin-right: 20px;
    float: right;
  }
  ul {
    padding-top: 80px;
  }
  ul li{
    display: none;
    width: 200px;
    height: 60px;
    float: none;
    margin: 0 auto;
  }
  ul li:first-of-type{
    margin: 0 auto;
/*    padding-top: 80px;*/
  }
  ul li.current{
    border: 0.5vh solid #888;
    box-sizing: border-box;
    margin: 0 auto;
  }
  .hamburger.active ~ ul li{
    display: block;
  }
  .hamburger.active ~ ul {
    height: 380px;
  }
}