* {
  margin: 0;
  padding: 0;
}

.container {
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: aliceblue;
}

input {
  display: none;
}

.btn {
  width: 200px;
  height: 100px;
  background-color: #c1c1c1;
  border-radius: 200px;
  cursor: pointer;
  position: relative;
}

.btn::before {
  position: absolute;
  content: '';
  height: 90px;
  width: 90px;
  background-color: #fff;
  border-radius: 200px;
  margin: 5px;
  transition: transform 0.2s ease-in-out;
}

input:checked+.btn {
  background-color: #dc143c;
}

input:checked+.btn::before {
  transform: translateX(calc(100% + 10px));
}