.menu-box {
  position: fixed;
  top: 0;
  text-align: right;
  width: 100%;
  padding: 10px 30px 10px 10px;
  box-sizing: border-box;
  z-index: 1000; 
}

.menu-box .menu-btn {
  width: 100%;
  display:inline;	
  padding:6px 3px 3px 3px;
  border: 2px solid #013399;
  border-radius: 3px;
}
.menu-box ul {
  display: none;
  width: 100%;
  background-color: #ccc;
}
.menu-box ul li a {
  display: block;
  font-family: "ヒラギノ角ゴ ProN W3", "Hiragino Kaku Gothic ProN", "メイリオ", "Meiryo", "verdana", sans-serif;
  border-bottom: 1px solid #fff;
  padding: 1em 0.7em;
  background-color: #013399;
}
.menu-box ul li:last-child a {
  border-bottom: none;
}
.menu-btn:after {
  content: '\f0c9';
  font-family: "Font Awesome 5 Free";
  font-weight: bold;
  color: #013399;
  font-size: 2.0rem;
  margin:0 0 0 3px;
}
.menu-btn.active:after {
  content: '\f00d';
}