<form action="">
      <div class="steps">
        <div class="step">
          <label for="step--1">1</label>
          <input id="step--1" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--2">2</label>
          <input id="step--2" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--3">3</label>
          <input id="step--3" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--4">4</label>
          <input id="step--4" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--5">5</label>
          <input id="step--5" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--6">6</label>
          <input id="step--6" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--7">7</label>
          <input id="step--7" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--8">8</label>
          <input id="step--8" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--9">9</label>
          <input id="step--9" type="checkbox" tabindex="-1" />
        </div>
        <div class="step">
          <label for="step--10">10</label>
          <input id="step--10" type="checkbox" tabindex="-1" />
        </div>
      </div>
      <button type="reset">Reset</button>
    </form>

*,
*:after,
*:before {
	box-sizing: border-box;
}

form {
	display: grid;
	place-items: center;
	align-content: center;
	grid-gap: var(--size-fluid-3);
  height: 100vh;
  width: 100vw;
}

body {
  display: grid;
  place-items: center;
  min-height: 100vh;
	font-family:  'Google Sans', sans-serif, system-ui;
  grid-auto-flow: column;
  background: hsl(var(--hue) 20% 50%);
}

.steps {
	display: flex;
	flex-wrap: wrap;
	justify-content: center;
	align-items: center;
}

.step {
  height: var(--size-fluid-6);
  position: relative;
  aspect-ratio: 1;
  background: hsl(var(--hue, 10) 80% 50% / 0.25);
}

button {
	display: block;
	padding: var(--size-2) var(--size-4);
	font-weight: bold;
	background: var(--gray-2);
	color: var(--gray-9);
}

button:hover {
	background: var(--gray-4);
}

[for] {
  background: var(--gray-4);
  color: var(--gray-9);
  font-weight: bold;
  font-size: var(--font-size-fluid-3);
  position: absolute;
  inset: 0;
  cursor: pointer;
  line-height: var(--size-fluid-6);
  text-align: center;
}

[for]:hover {
  background: var(--gray-3);
}

:is(.step) {
	--hue: 10;
  pointer-events: none;
  opacity: 0.1;
}

:is(.step:first-of-type) {
  --hue: 210;
  pointer-events: all;
  opacity: 1;
}

.step:has(:checked), .step:first-of-type:has(:checked) {
  --hue: 10;
  pointer-events: none;
  opacity: 0.2;
}


.step:has(:checked) + .step:not(.step:has(:checked)) {
  --hue: 210;
  pointer-events: all;
  opacity: 1;
}

:root:has(#step--10:checked) {
  --hue: 130;
}