input.switch {
  -webkit-appearance: none;
  width: 34px;
  height: 18px;
  border: 2px solid var(--border-color);
  position: relative;
  border-radius: 50px;
  box-sizing: content-box;
  cursor: pointer;
  transition: background 150ms ease-in-out;
  background: white;
}

input.switch::after {
  top: 2px;
  left: 2px;
  transition: left 150ms ease-in-out;
  content: " ";
  width: 14px;
  height: 14px;
  background: var(--border-color);
  box-shadow: inset 0 0 0px 1px var(--border-color);
  position: absolute;
  border-radius: 50px;
}

input.switch:checked {
  background: var(--secondary);
}

input.switch:checked::after {
  left: calc(100% - 17px);
  background: var(--background);
}