/* ----------ドロワーメニュー----------- */
/*  https://tivel.jp/archives/11037#i-2  */
/* ------------------------------------  */

.overlay {
  content: "";
  display: block;
  width: 0;
  height: 0;
  background: #000000;
  opacity: 0.5;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 2;
  opacity: 0;
  transition: opacity .5s;
}
.overlay.open {
  width: 100%;
  height: 100%;
  opacity: 1;
}
.menu-trigger {
  display: inline-block;
  width: 35px;
  height: 28px;
  vertical-align: middle;
  cursor: pointer;
  position: fixed;
  top: 15px;
  right: 18px;
  z-index: 100;
  transform: translateX(0);
  transition: transform .5s;
 }
 .menu-trigger.active {
  transform: translateX(-250px);
}
.menu-trigger span {
display: inline-block;
box-sizing: border-box;
position: absolute;
left: 0;
width: 100%;
height: 4px;
background-color: #000000;
}
.menu-trigger.active span {
  background-color: #000000;
}
.menu-trigger span:nth-of-type(1) {
  top: 0;
}
.menu-trigger.active span:nth-of-type(1) {
  transform: translateY(12px) rotate(-45deg);
}
.menu-trigger span:nth-of-type(2) {
  top: 12px;
}
.menu-trigger.active span:nth-of-type(2) {
  opacity: 0;
}
.menu-trigger span:nth-of-type(3) {
  bottom: 0;
}
.menu-trigger.active span:nth-of-type(3) {
  transform: translateY(-12px) rotate(45deg);
}

nav {
  width: 250px;
  height: 100%;
  padding-top: 50px;
  background: #000000;
  opacity: 0.5;
  position: fixed;
  top: 0;
  right: 0;
  z-index: 10;
  transform: translate(250px);
  transition: all .5s;
}
nav.open {
  transform: translateZ(0);
}