:root {
	--lerp-0: 1;
  --lerp-1: 0.5625;
  --lerp-2: 0.25;
  --lerp-3: 0.0625;
  --lerp-4: 0;
}

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

h1 {
  position: fixed;
  bottom: var(--size-4);
  right: var(--size-4);
  margin: 0;
  color: var(--gray-0);
}

body {
	display: grid;
	place-items: center;
	min-height: 100vh;
	font-family:  'Google Sans', sans-serif, system-ui;
	background: var(--gradient-1);
}

:root {
  --lerp-0: 1;
  --lerp-1: 0.5625;
  --lerp-2: 0.25;
  --lerp-3: 0.0625;
  --lerp-4: 0;
}

.blocks {
	display: flex;
	list-style-type: none;
	padding: var(--size-2);
	border-radius: var(--radius-3);
	gap: var(--size-4);
	background: hsl(0 0% 100% / 0.5);
	align-items: center;
	justify-content: center;
	align-content: center;
	-webkit-backdrop-filter: blur(10px);
	        backdrop-filter: blur(10px);
}

.blocks:hover {
	--show: 1;
}

.block {
	width: 48px;
	height: 48px;
	display: grid;
	place-items: center;
	align-content: center;
	transition: flex 0.2s;
	flex: calc(0.2 + (var(--lerp, 0) * 1.5));
	position: relative;
}

.block:after {
	content: '';
	width: 5%;
	aspect-ratio: 1;
	background: var(--text-1);
	position: absolute;
	bottom: 10%;
	left: 50%;
	border-radius: var(--radius-3);
	transform: translate(-50%, -50%);
	z-index: -1;
}

.block:before {
	content: '';
	position: absolute;
	width: calc(100% + var(--size-4));
	bottom: 0;
	aspect-ratio: 1 / 2;
	left: 50%;
	transition: transform 0.2s;
	transform-origin: 50% 100%;
	transform: translateX(-50%) scaleY(var(--show, 0));
	z-index: -1;
}

.block .block__item {
  transition: outline 0.2s;
  outline: transparent var(--size-1) solid;
}

:is(.block:hover, .block:focus-visible) .block__item {
	outline: var(--surface-1) var(--size-1) solid;
}

.block {
	outline: none;
}

.block__item {
	width: 100%;
	aspect-ratio: 1;
	border-radius: var(--radius-3);
	background: var(--bg), var(--surface-1);
	display: inline-block;
	transition: transform 0.2s;
	transform-origin: 50% 100%;
	position: relative;
	transform: translateY(calc(var(--lerp) * -75%));
}

.block__item:after {
	content: '';
	position: absolute;
	height: 100%;
	top: 50%;
	left: 50%;
	transform: translate(-50%, -50%);
	aspect-ratio: 1;
	border-left: var(--size-2) solid white;
	border-top: var(--size-2) solid white;
	border-radius: var(--radius-3);
	-webkit-mask: linear-gradient(135deg, black, transparent 50%);
	        mask: linear-gradient(135deg, black, transparent 50%);
}

@media(prefers-color-scheme: dark) {
	body {
		background: var(--gradient-23);
	}
	.blocks {
		background: hsl(0 0% 0% / 0.5);
	}
}


:is(.block:hover, .block:focus-visible) {
  --lerp: var(--lerp-0);
  z-index: 5;
}
.block:has( + :is(.block:hover, .block:focus-visible)),
:is(.block:hover, .block:focus-visible) + .block {
  --lerp: var(--lerp-1);
  z-index: 4;
}
.block:has( + .block + :is(.block:hover, .block:focus-visible)),
:is(.block:hover, .block:focus-visible) + .block + .block {
  --lerp: var(--lerp-2);
  z-index: 3;
}
.block:has( + .block + .block + :is(.block:hover, .block:focus-visible)),
:is(.block:hover, .block:focus-visible) + .block + .block + .block {
  --lerp: var(--lerp-3);
  z-index: 2;
}
.block:has( + .block + .block + .block + :is(.block:hover, .block:focus-visible)),
:is(.block:hover, .block:focus-visible) + .block + .block + .block + .block {
  --lerp: var(--lerp-4);
  z-index: 1;
}


body:has(a[style="--bg: var(--gradient-1);"]:focus) {
	background: var(--gradient-1);
}
body:has(a[style="--bg: var(--gradient-2);"]:focus) {
	background: var(--gradient-2);
}
body:has(a[style="--bg: var(--gradient-3);"]:focus) {
	background: var(--gradient-3);
}
body:has(a[style="--bg: var(--gradient-4);"]:focus) {
	background: var(--gradient-4);
}
body:has(a[style="--bg: var(--gradient-5);"]:focus) {
	background: var(--gradient-5);
}
body:has(a[style="--bg: var(--gradient-6);"]:focus) {
	background: var(--gradient-6);
}
body:has(a[style="--bg: var(--gradient-7);"]:focus) {
	background: var(--gradient-7);
}
body:has(a[style="--bg: var(--gradient-8);"]:focus) {
	background: var(--gradient-8);
}
body:has(a[style="--bg: var(--gradient-9);"]:focus) {
	background: var(--gradient-9);
}