/* see anim&grafik > toggle burger */
button#burger {
  position: absolute;
  top: 0;
  right: 0;
  border: none;
  background: transparent;
  padding: 0;
  transition: 0.3s;
  cursor: pointer;
  user-select: none;
  border-radius: 0.28571rem;
  opacity: 0.95;
  outline: none;
}
button#burger:hover {
  opacity: 1;
}
button#burger:active {
  transition: 0;
  background: rgba(0, 0, 0, 0.1);
}

.burger-line {
  display: inline-block;
  width: 2rem;
  height: 0.28571rem;
  background: #fff;
  border-radius: 0.14286rem;
  transition: all 0.3s;
  position: relative;
}
.burger-line:before,
.burger-line:after {
  display: inline-block;
  width: 2rem;
  height: 0.28571rem;
  background: #fff;
  border-radius: 0.14286rem;
  transition: 0.3s;
  position: absolute;
  left: 0;
  content: "";
  transform-origin: 0.14286rem center;
}
.burger-line:before {
  top: 0.5rem;
}
.burger-line:after {
  top: -0.5rem;
}

#burger.xcross .burger-line {
  background: transparent;
}
#burger.xcross .burger-line:before,
#burger.xcross .burger-line:after {
  transform-origin: 50% 50%;
  top: 0;
  width: 2rem;
}
#burger.xcross .burger-line:before {
  transform: rotate3d(0, 0, 1, 45deg);
}
#burger.xcross .burger-line:after {
  transform: rotate3d(0, 0, 1, -45deg);
}