.burger {
  position: fixed;
  top: 8px;
  right: 20px;
  width: 30px;
  height: 30px;
  cursor: pointer;
  z-index: 20;
}
.burger span {
  display: block;
  height: 3px;
  width: 100%;
  background-color: #333;
  margin: 5px 0;
  transition: 0.4s;
}
.burger.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.burger.active span:nth-child(2) {
  opacity: 0;
}
.burger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}
.menu {
  position: fixed;
  top: 0;
  right: -100%;
  width: 320px;
  height: auto;
  background: #fff;
  padding: 20px;
  box-sizing: border-box;
  transition: right 0.3s ease;
  z-index: 10;
  border: 1px solid #eee;
  box-shadow: 8px 8px 8px #aaa;
  max-height: 95vh;
  overflow: auto;
}
.menu.open {
  right: 0;
}
.menu ul {
  list-style: none;
  padding: 0;
  margin-bottom: 0;
}
.menu li {
  padding-top: 1rem;
}
.menu li a {
  color: #000;
  text-decoration: none;
}
.menu li a:hover {
  text-decoration: underline;
}