@import url('https://fonts.googleapis.com/css2?family=DM+Mono:wght@400;500&family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
	--ink: #182329;
	--muted: #789096;
	--paper: #f3f6f1;
	--calculator: #ffffff;
	--line: #e7ece8;
	--key: #f6f8f5;
	--key-hover: #edf2ed;
	--operator: #dff2e8;
	--operator-ink: #19734d;
	--accent: #237d55;
	--accent-dark: #1d6848;
	--shadow: 0 28px 70px rgba(39, 75, 57, 0.14), 0 4px 12px rgba(39, 75, 57, 0.05);
}

* {
	box-sizing: border-box;
}

html,
body {
	width: 100%;
	height: 100%;
	overflow: hidden;
}

body {
	min-width: 300px;
	margin: 0;
	color: var(--ink);
	background: radial-gradient(circle at 50% -15%, #ffffff 0, var(--paper) 48%, #e9f0e9 100%);
	font-family: 'Space Grotesk', sans-serif;
}

button {
	font: inherit;
}

.page-shell {
	display: grid;
	position: relative;
	height: 100vh;
	height: 100dvh;
	place-items: center;
	padding: 32px 20px;
	overflow: hidden;
	isolation: isolate;
}

.math-backdrop {
	position: absolute;
	inset: -5%;
	z-index: 0;
	display: grid;
	grid-template-columns: repeat(4, minmax(0, 1fr));
	grid-template-rows: repeat(4, minmax(0, 1fr));
	align-items: center;
	justify-items: center;
	color: rgba(35, 125, 85, 0.13);
	font-family: 'DM Mono', monospace;
	font-size: 16px;
	transform: rotate(-8deg) scale(1.05);
	pointer-events: none;
	user-select: none;
}

.math-backdrop span:nth-child(3n + 1) {
	color: rgba(35, 125, 85, 0.17);
}

.math-backdrop span:nth-child(3n + 2) {
	color: rgba(161, 97, 57, 0.14);
}

.calculator {
	position: relative;
	z-index: 1;
	width: min(100%, 392px);
	padding: 24px;
	border: 1px solid rgba(255, 255, 255, 0.85);
	border-radius: 28px;
	background: var(--calculator);
	box-shadow: var(--shadow);
}

.calculator__topbar {
	display: flex;
	align-items: center;
	gap: 12px;
	margin-bottom: 22px;
}

.brand-mark {
	position: relative;
	display: grid;
	width: 42px;
	height: 42px;
	place-items: center;
	border-radius: 13px;
	color: #fff;
	background: var(--accent);
	font-size: 25px;
	font-weight: 500;
	box-shadow: 0 8px 14px rgba(35, 125, 85, 0.22);
}

.brand-mark__screen {
	position: absolute;
	top: 9px;
	width: 23px;
	height: 8px;
	border: 2px solid rgba(255, 255, 255, 0.92);
	border-radius: 3px;
}

.brand-mark__keys {
	position: absolute;
	bottom: 9px;
	width: 21px;
	height: 14px;
	background: radial-gradient(circle, #fff 0 2px, transparent 2.5px) 0 0 / 7px 7px;
}

.eyebrow {
	margin: 0 0 2px;
	color: var(--muted);
	font-size: 10px;
	font-weight: 600;
	letter-spacing: 0.12em;
	text-transform: uppercase;
}

h1 {
	margin: 0;
	font-size: 20px;
	line-height: 1;
}

.status-dot {
	width: 7px;
	height: 7px;
	margin-left: auto;
	border-radius: 50%;
	background: #58b77e;
	box-shadow: 0 0 0 4px #e4f6ea;
}

.display {
	display: flex;
	min-height: 142px;
	flex-direction: column;
	justify-content: flex-end;
	align-items: flex-end;
	padding: 20px 4px 26px;
	border-bottom: 1px solid var(--line);
	overflow: hidden;
}

.display__expression {
	width: 100%;
	min-height: 20px;
	overflow: hidden;
	color: var(--muted);
	font-family: 'DM Mono', monospace;
	font-size: 13px;
	text-align: right;
	text-overflow: ellipsis;
	white-space: nowrap;
}

.display__value {
	width: 100%;
	overflow: hidden;
	color: var(--ink);
	font-family: 'DM Mono', monospace;
	font-size: clamp(36px, 10vw, 52px);
	font-weight: 500;
	letter-spacing: -0.04em;
	text-align: right;
	text-overflow: ellipsis;
	white-space: nowrap;
}

.keypad {
	display: grid;
	grid-template-columns: repeat(4, 1fr);
	gap: 11px;
	padding-top: 22px;
}

.key {
	min-height: 61px;
	border: 0;
	border-radius: 16px;
	color: var(--ink);
	background: var(--key);
	cursor: pointer;
	font-size: 20px;
	font-weight: 600;
	transition: transform 120ms ease, background 120ms ease, box-shadow 120ms ease;
	-webkit-tap-highlight-color: transparent;
}

.key:hover {
	background: var(--key-hover);
}

.key:active,
.key.is-pressed {
	transform: scale(0.94);
}

.key:focus-visible {
	outline: 3px solid rgba(35, 125, 85, 0.34);
	outline-offset: 2px;
}

.key--wide {
	grid-column: span 2;
}

.key--utility {
	color: #a16139;
	background: #fff4ec;
	font-size: 15px;
}

.key--operator {
	color: var(--operator-ink);
	background: var(--operator);
	font-size: 25px;
}

.key--equals {
	color: #fff;
	background: var(--accent);
	box-shadow: 0 8px 14px rgba(35, 125, 85, 0.2);
	font-size: 28px;
}

.key--equals:hover {
	background: var(--accent-dark);
}

.hint {
	position: relative;
	z-index: 1;
	margin: 20px 0 0;
	color: var(--muted);
	font-size: 11px;
	text-align: center;
}

@media (max-width: 420px) {
	.page-shell {
		padding: 16px 12px;
	}

	.math-backdrop {
		grid-template-columns: repeat(3, minmax(0, 1fr));
		grid-template-rows: repeat(6, minmax(0, 1fr));
		font-size: 14px;
	}

	.calculator {
		padding: 18px;
		border-radius: 23px;
	}

	.keypad {
		gap: 8px;
		padding-top: 18px;
	}

	.key {
		min-height: 58px;
		border-radius: 14px;
	}
}

@media (max-height: 760px) and (min-width: 421px) {
	.page-shell {
		padding: 20px;
	}

	.display {
		min-height: 112px;
		padding-top: 14px;
		padding-bottom: 20px;
	}

	.keypad {
		gap: 8px;
		padding-top: 16px;
	}

	.key {
		min-height: 54px;
	}

	.hint {
		margin-top: 12px;
	}
}