<label class="switch">
  <input class="switch__input" type="checkbox" role="switch">
  <svg class="switch__icon switch__icon--light" viewBox="0 0 12 12" width="12px" height="12px" aria-hidden="true">
    <g fill="none" stroke="#fff" stroke-width="1" stroke-linecap="round">
      <circle cx="6" cy="6" r="2" />
      <g stroke-dasharray="1.5 1.5">
        <polyline points="6 10,6 11.5" transform="rotate(0,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(45,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(90,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(135,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(180,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(225,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(270,6,6)" />
        <polyline points="6 10,6 11.5" transform="rotate(315,6,6)" />
      </g>
    </g>
  </svg>
  <svg class="switch__icon switch__icon--dark" viewBox="0 0 12 12" width="12px" height="12px" aria-hidden="true">
    <g fill="none" stroke="#fff" stroke-width="1" stroke-linejoin="round" transform="rotate(-45,6,6)">
      <path d="m9,10c-2.209,0-4-1.791-4-4s1.791-4,4-4c.304,0,.598.041.883.105-.995-.992-2.367-1.605-3.883-1.605C2.962.5.5,2.962.5,6s2.462,5.5,5.5,5.5c1.516,0,2.888-.613,3.883-1.605-.285.064-.578.105-.883.105Z"/>
    </g>  
  </svg>
  <span class="switch__sr">Dark Mode</span>
</label>

* {
  border: 0;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
:root {
  --hue: 223;
  --bg: hsl(var(--hue),10%,90%);
  --fg: hsl(var(--hue),10%,10%);
  --primary: hsl(var(--hue),90%,50%);
  --trans-dur: 0.3s;
  --trans-timing: cubic-bezier(0.76,0.05,0.24,0.95);
  --trans-timing-in: cubic-bezier(0.76,0.05,0.86,0.06);
  --trans-timing-out: cubic-bezier(0.05,0.76,0.06,0.86);
  font-size: calc(40px + (80 - 40) * (100vw - 320px) / (2560 - 320));
}
body,
input {
  color: var(--fg);
  font: 1em/1.5 sans-serif;
}
body {
  background-color: var(--bg);
  display: flex;
  height: 100vh;
  transition:
    background-color var(--trans-dur),
    color var(--trans-dur);
}
body:has(.switch__input:checked) {
  background-color: var(--fg);
  color: var(--bg);
}
.switch {
  margin: auto;
  position: relative;
}
.switch__icon,
.switch__input {
  display: block;
}
.switch__icon {
  position: absolute;
  top: 0.375em;
  right: 0.375em;
  width: 0.75em;
  height: 0.75em;
  transition:
    opacity calc(var(--trans-dur) / 2),
    transform calc(var(--trans-dur) / 2);
}
.switch__icon polyline {
  transition: stroke-dashoffset calc(var(--trans-dur) / 2);
}
.switch__icon--light,
.switch__icon--light polyline {
  transition-delay: calc(var(--trans-dur) / 2);
  transition-timing-function: var(--trans-timing-out);
}
.switch__icon--dark {
  opacity: 0;
  transform: translateX(-0.75em) rotate(30deg) scale(0.75);
  transition-timing-function: var(--trans-timing-in);
}
.switch__input {
  background-color: hsl(210,90%,70%);
  border-radius: 0.75em;
  box-shadow:
    0 0 0 0.125em hsla(var(--hue),90%,50%,0),
    0.125em 0.125em 0.25em hsla(var(--hue),90%,10%,0.2);
  outline: transparent;
  position: relative;
  width: 3em;
  height: 1.5em;
  -webkit-appearance: none;
  appearance: none;
  -webkit-tap-highlight-color: transparent;
  transition:
    background-color var(--trans-dur) var(--trans-timing),
    box-shadow 0.15s linear;
}
.switch__input:focus-visible {
  box-shadow:
    0 0 0 0.125em hsl(var(--hue),90%,50%),
    0.125em 0.125em 0.25em hsla(var(--hue),90%,10%,0.2);
}
.switch__input:before,
.switch__input:after {
  content: "";
  display: block;
  position: absolute;
}
.switch__input:before {
  background-color: hsl(50,90%,50%);
  border-radius: inherit;
  mask-image: linear-gradient(120deg,hsl(0,0%,0%) 20%,hsla(0,0%,0%,0) 80%);
  -webkit-mask-image: linear-gradient(120deg,hsl(0,0%,0%) 20%,hsla(0,0%,0%,0) 80%);
  inset: 0;
  transition: background-color var(--trans-dur) var(--trans-timing);
}
.switch__input:after {
  background-color: hsl(0,0%,100%);
  border-radius: 50%;
  box-shadow: 0.05em 0.05em 0.05em hsla(var(--hue),90%,10%,0.1);
  top: 0.125em;
  left: 0.125em;
  width: 1.25em;
  height: 1.25em;
  transition:
    background-color var(--trans-dur) var(--trans-timing),
    transform var(--trans-dur) var(--trans-timing);
  z-index: 1;
}
.switch__input:checked {
  background-color: hsl(290,90%,40%);
}
.switch__input:checked:before {
  background-color: hsl(220,90%,40%);
}
.switch__input:checked:after {
  background-color: hsl(0,0%,0%);
  transform: translateX(1.5em);
}
.switch__input:checked ~ .switch__icon--light,
.switch__input:checked ~ .switch__icon--light polyline {
  transition-delay: 0s;
  transition-timing-function: var(--trans-timing-in);
}
.switch__input:checked ~ .switch__icon--light {
  opacity: 0;
  transform: translateX(-0.75em) rotate(-30deg) scale(0.75);
}
.switch__input:checked ~ .switch__icon--light polyline {
  stroke-dashoffset: 1.5;
}
.switch__input:checked ~ .switch__icon--dark {
  opacity: 1;
  transform: translateX(-1.5em);
  transition-delay: calc(var(--trans-dur) / 2);
  transition-timing-function: var(--trans-timing-out);
}
.switch__sr {
  overflow: hidden;
  position: absolute;
  width: 1px;
  height: 1px;
}