html {
  scrollbar-gutter: stable;
}
.hamburger-overlay {
  position: absolute;
  z-index: 1000;
  border: none;
  background: transparent;
  cursor: pointer;
  width: 60px;
  height: 60px;
  top: 10px; 
  right: 20px;
}

.hamburger-overlay-line {
  position: absolute;
  left: 10px;
  width: 40px;
  height: 4px;
  background-color: #ffffff;
  transition: all .6s;
}

#overlay-menu{
  /* height: 100vh; */
  overflow: auto;
}

.hamburger-overlay-line:nth-of-type(1) { top: 16px; }
.hamburger-overlay-line:nth-of-type(2) { top: 28px; }
.hamburger-overlay-line:nth-of-type(3) { top: 40px; }


.hamburger-overlay.active .hamburger-overlay-line {
  background-color: #000000;
}

.hamburger-overlay.active .hamburger-overlay-line:nth-of-type(2) {
  opacity: 0;
}

.hamburger-overlay.active .hamburger-overlay-line:nth-of-type(1) {
  transform: translateY(12px) rotate(-45deg);
}
.hamburger-overlay.active .hamburger-overlay-line:nth-of-type(3) {
  transform: translateY(-12px) rotate(45deg);
}


.nav-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: rgba(255, 255, 255, 0.95);
  visibility: hidden;
  opacity: 0;
  transition: all .6s;
  z-index: 900;
}

.nav-overlay.active {
  visibility: visible;
  opacity: 1;
}

.nav-overlay-content {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 100%;
  text-align: center;
}

.nav-overlay-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-overlay-item {
  opacity: 0;
  transform: translateY(20px);
  transition: all .6s;
}

.nav-overlay.active .nav-overlay-item {
  opacity: 1;
  transform: translateY(0);
}

.nav-overlay.active .nav-overlay-item:nth-child(1) { transition-delay: 0.1s; }
.nav-overlay.active .nav-overlay-item:nth-child(2) { transition-delay: 0.2s; }
.nav-overlay.active .nav-overlay-item:nth-child(3) { transition-delay: 0.3s; }
.nav-overlay.active .nav-overlay-item:nth-child(4) { transition-delay: 0.4s; }

.nav-overlay-link {
  display: inline-block;
  padding: 20px;
  color: #000;
  font-size: 24px;
  text-decoration: none;
  transition: color .3s;
}

.nav-overlay-link:hover {
  color: #4a90e2;
}

/* 検証用 */