<label class="switch">
  <input type="checkbox" checked/>
  <div class="indicator left"></div>
  <div class="indicator right"></div>
  <div class="button"></div>
</label>
body, html {
  width: 100vw;
  height: 100vh;
}

body {
  background-image: linear-gradient(135deg, hsl(var(--hue) 20% 95%), hsl(var(--hue) 20% 80%));
  display: flex;
  align-items: center;
  justify-content: center;
  --hue: 220deg;
  --width: 23rem;
  --accent-hue: 22deg;
  --duration: 0.6s;
  --easing: cubic-bezier(1, 0, 1, 1);
}

input {
  display: none;
}

.switch {
  --shadow-offset: calc(var(--width) / 20);
  position: relative;
  cursor: pointer;
  display: flex;
  align-items: center;
  width: var(--width);
  height: calc(var(--width) / 2.5);
  border-radius: var(--width);
  box-shadow: 
    inset 10px 10px 10px hsl(var(--hue) 20% 80%),
    inset -10px -10px 10px hsl(var(--hue) 20% 93%);
}

.indicator {
  content: '';
  position: absolute;
  width: 40%;
  height: 60%;
  transition: all var(--duration) var(--easing);
  box-shadow: 
    inset 0 0 2px hsl(var(--hue) 20% 15% / 60%),
    inset 0 0 3px 2px hsl(var(--hue) 20% 15% / 60%),
    inset 0 0 5px 2px hsl(var(--hue) 20% 45% / 60%);
}

.indicator.left {
  --hue: var(--accent-hue);
  overflow: hidden;
  left: 10%;
  border-radius: 100px 0 0 100px;
  background: linear-gradient(180deg, hsl(calc(var(--accent-hue) + 20deg) 95% 80%) 10%, hsl(calc(var(--accent-hue) + 20deg) 100% 60%) 30%, hsl(var(--accent-hue) 90% 50%) 60%, hsl(var(--accent-hue) 90% 60%) 75%, hsl(var(--accent-hue) 90% 50%));
}

.indicator.left::after {
  content: '';
  position: absolute;
  opacity: 0.6;
  width: 100%;
  height: 100%;
  background: url("data:image/svg+xml;base64,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");
}

.indicator.right {
  right: 10%;
  border-radius: 0 100px 100px 0;
  background-image: linear-gradient(180deg, hsl(var(--hue) 20% 95%), hsl(var(--hue) 20% 65%) 60%, hsl(var(--hue) 20% 70%) 70%, hsl(var(--hue) 20% 65%));
}

.button {
  position: absolute;
  z-index: 1;
  width: 55%;
  height: 80%;
  left: 5%;
  border-radius: 100px;
  background-image: linear-gradient(160deg, hsl(var(--hue) 20% 95%) 40%, hsl(var(--hue) 20% 65%) 70%);
  transition: all var(--duration) var(--easing);
  box-shadow:
    2px 2px 3px hsl(var(--hue) 18% 50% / 80%),
    2px 2px 6px hsl(var(--hue) 18% 50% / 40%),
    10px 20px 10px hsl(var(--hue) 18% 50% / 40%),
    20px 30px 30px hsl(var(--hue) 18% 50% / 60%);
}

.button::before, 
.button::after {
  content: '';
  position: absolute;
  top: 10%;
  width: 41%;
  height: 80%;
  border-radius: 100%;
}

.button::before {
  left: 5%;
  box-shadow: inset 1px 1px 2px hsl(var(--hue) 20% 85%);
  background-image: linear-gradient(-50deg, hsl(var(--hue) 20% 95%) 20%, hsl(var(--hue) 20% 85%) 80%);
}

.button::after {
  right: 5%;
  box-shadow: inset 1px 1px 3px hsl(var(--hue) 20% 70%);
  background-image: linear-gradient(-50deg, hsl(var(--hue) 20% 95%) 20%, hsl(var(--hue) 20% 75%) 80%);
}

input:checked ~ .button {
  left: 40%;
}

input:not(:checked) ~ .indicator.left,
input:checked ~ .indicator.right {
  box-shadow: 
    inset 0 0 5px hsl(var(--hue) 20% 15% / 100%),
    inset 20px 20px 10px hsl(var(--hue) 20% 15% / 100%),
    inset 20px 20px 15px hsl(var(--hue) 20% 45% / 100%);
}

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