.backdrop {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  visibility: hidden;
  background: rgba(0, 0, 0, 0.4);
  z-index: 998;
  cursor: pointer;
}

.backdrop--open {
  visibility: visible;
}

.panel {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 30rem;
  background-color: var(--background-color);
  z-index: 999;
  padding: 1.5rem;
  transform: translateX(100%);
  transition: transform 0.3s ease-in-out;
  overflow: auto;
}

.panel--open {
  transform: translate(0);
}
