* {
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  transition: background 0.4s linear;
  font-weight: bold;
}
body .goodnight {
  display: none;
  font-weight: 700;
}
body.dark {
  background-color: #292c35;
  transition: background 0.4s linear;
  color: white;
}

body.dark .goodmorning {
  display: none;
}
body.dark .goodnight {
  display: block;
}

.label {
  position: relative;
  display: flex;
  width: 50px;
  height: 26px;
  background: #111;
  border-radius: 50px;
  cursor: pointer;
  align-items: center;
  padding: 5px;
  justify-content: space-between;
}

.checkbox {
  position: absolute;
}

.fa-moon {
  color: #f1c40f;
}

.fa-sun {
  color: #f38c12;
}
.ball {
  position: absolute;
  width: 20px;
  height: 20px;
  background-color: white;
  border-radius: 20px;
  transition: transform 0.3s linear;
}
.checkbox:checked + .label .ball {
  transform: translateX(24px);
}