/* The Rusuban design system: Paper by day, Matsu by night, one vermilion seal on what waits for the owner. */
:root {
	--page: #fbfbfa;
	--shell: #f4f4f2;
	--surface: #ffffff;
	--surface-raised: #f1f1ef;
	--line: rgba(27, 26, 24, 0.09);
	--line-strong: rgba(27, 26, 24, 0.16);
	--fill: rgba(27, 26, 24, 0.04);
	--ink: #1b1a18;
	--ink-muted: #57554f;
	--ink-faint: #6b6963;
	--on-ink: #ffffff;
	--seal: #b83a24;
	--on-seal: #ffffff;
	--accent: #b83a24;
	--accent-soft: #fbe9e5;
	--positive: #237a4b;
	--kind-feature: #43648c;
	--shadow-float: 0 8px 24px rgba(0, 0, 0, 0.06);
	--radius-xs: 4px;
	--radius-sm: 6px;
	--radius-md: 10px;
	--radius-lg: 14px;
	--radius-xl: 20px;
	--radius-pill: 999px;
	--font-display: "Zen Kaku Gothic New", "Hiragino Sans", "Yu Gothic", system-ui, sans-serif;
	--font-sans: Inter, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
	--font-mono: "JetBrains Mono", ui-monospace, "Cascadia Mono", Consolas, monospace;
	--font-seal: "Noto Serif JP", "Hiragino Mincho ProN", "Yu Mincho", serif;
	--ease: cubic-bezier(0.22, 1, 0.36, 1);
	color-scheme: light;
}
@media (prefers-color-scheme: dark) {
	:root:not([data-theme="light"]) {
		--page: #101a12;
		--shell: #0c140e;
		--surface: #18241b;
		--surface-raised: #202e23;
		--line: rgba(236, 240, 228, 0.09);
		--line-strong: rgba(236, 240, 228, 0.16);
		--fill: rgba(236, 240, 228, 0.05);
		--ink: #eef0e6;
		--ink-muted: #acb5a6;
		--ink-faint: #8f9a89;
		--on-ink: #101a12;
		--accent: #f26e52;
		--accent-soft: rgba(242, 110, 82, 0.14);
		--positive: #a8c69c;
		--kind-feature: #93abcb;
		--shadow-float: 0 8px 24px rgba(0, 0, 0, 0.4);
		color-scheme: dark;
	}
}
:root[data-theme="dark"] {
	--page: #101a12;
	--shell: #0c140e;
	--surface: #18241b;
	--surface-raised: #202e23;
	--line: rgba(236, 240, 228, 0.09);
	--line-strong: rgba(236, 240, 228, 0.16);
	--fill: rgba(236, 240, 228, 0.05);
	--ink: #eef0e6;
	--ink-muted: #acb5a6;
	--ink-faint: #8f9a89;
	--on-ink: #101a12;
	--accent: #f26e52;
	--accent-soft: rgba(242, 110, 82, 0.14);
	--positive: #a8c69c;
	--kind-feature: #93abcb;
	--shadow-float: 0 8px 24px rgba(0, 0, 0, 0.4);
	color-scheme: dark;
}

* {
	box-sizing: border-box;
}
body {
	margin: 0;
	background: var(--page);
	color: var(--ink);
	font: 400 16px / 26px var(--font-sans);
	font-variant-numeric: tabular-nums;
}
a {
	color: var(--ink);
	text-underline-offset: 3px;
}
a:hover {
	color: var(--ink-muted);
}
:focus-visible {
	outline: 2px solid var(--ink);
	outline-offset: 2px;
}
h1,
h2,
h3 {
	margin: 0;
	font-family: var(--font-display);
	font-weight: 500;
	color: var(--ink);
	text-wrap: balance;
}
p {
	margin: 0;
}
/* The fonts load 400 and 500: a bold would be drawn by the browser */
strong {
	font-weight: 500;
}
code {
	font-family: var(--font-mono);
}
.wrap {
	max-width: 1184px;
	margin: 0 auto;
	padding-left: max(32px, env(safe-area-inset-left, 0px));
	padding-right: max(32px, env(safe-area-inset-right, 0px));
}
.muted {
	color: var(--ink-muted);
}
.section {
	padding-block: 96px;
	display: flex;
	flex-direction: column;
	gap: 48px;
}
.section-head {
	display: flex;
	gap: 24px;
	align-items: flex-start;
	max-width: 760px;
}
.section-head > div {
	display: flex;
	flex-direction: column;
	gap: 12px;
}
.section h2,
.locks h2 {
	font-size: 40px;
	line-height: 48px;
	letter-spacing: -0.02em;
}
/* A Japanese mark beside each section title, in ink: the house that Rusuban minds */
.mark {
	flex: none;
	writing-mode: vertical-rl;
	padding-top: 4px;
	font: 500 40px / 1 var(--font-display);
	letter-spacing: 0.08em;
	color: var(--ink-faint);
}
.band {
	background: var(--shell);
	border-top: 1px solid var(--line);
	border-bottom: 1px solid var(--line);
}
.icon {
	width: 16px;
	height: 16px;
	flex: none;
	stroke: currentColor;
	fill: none;
	stroke-width: 1.5;
	stroke-linecap: round;
	stroke-linejoin: round;
}

/* Menus of the docs and the footer: quiet links, the current page on a raised step */
.doc-nav ul {
	margin: 0;
	padding: 0;
	list-style: none;
	display: grid;
	gap: 4px;
}
.doc-nav a {
	display: block;
	padding: 8px 12px;
	border-radius: var(--radius-sm);
	color: var(--ink-muted);
	text-decoration: none;
	font-size: 15px;
	line-height: 20px;
}
.doc-nav a:hover {
	color: var(--ink);
	background: var(--fill);
}
.doc-nav a[aria-current="page"] {
	color: var(--ink);
	background: var(--surface-raised);
}
.foot-cols a {
	color: var(--ink-muted);
	text-decoration: none;
	font-size: 14px;
	line-height: 20px;
}
.foot-cols a:hover {
	color: var(--ink);
}

/* The seal: the brand's mark, and the owner's */
.brand {
	display: inline-flex;
	align-items: center;
	gap: 12px;
	font: 500 18px / 1 var(--font-display);
	color: var(--ink);
	text-decoration: none;
}
.seal {
	display: inline-grid;
	place-items: center;
	flex: none;
	width: 32px;
	height: 32px;
	border-radius: var(--radius-sm);
	background: var(--seal);
	color: var(--on-seal);
	font: 700 19px / 1 var(--font-seal);
}
.seal-sm {
	width: 20px;
	height: 20px;
	font-size: 12px;
	border-radius: var(--radius-xs);
}

/* Header */
.top {
	border-bottom: 1px solid var(--line);
}
.top nav {
	display: flex;
	flex-wrap: wrap;
	align-items: center;
	gap: 12px 32px;
	padding-block: 16px;
}
.links {
	display: flex;
	flex-wrap: wrap;
	align-items: center;
	gap: 8px 24px;
	margin-left: auto;
}
.top .links a:not(.btn) {
	color: var(--ink-muted);
	text-decoration: none;
	font-size: 15px;
	transition: color 0.14s var(--ease);
}
.top .links a:not(.btn):hover {
	color: var(--ink);
}

/* Buttons */
.btn {
	display: inline-flex;
	align-items: center;
	gap: 8px;
	height: 36px;
	padding: 0 16px;
	border-radius: var(--radius-md);
	border: 1px solid var(--line-strong);
	background: var(--surface);
	color: var(--ink);
	font: 500 14px / 1 var(--font-sans);
	text-decoration: none;
	cursor: pointer;
	transition:
		background-color 0.14s var(--ease),
		transform 0.14s var(--ease);
}
.btn:hover {
	background: var(--surface-raised);
	color: var(--ink);
}
.btn:active {
	transform: scale(0.98);
}
.btn-primary {
	background: var(--ink);
	border-color: var(--ink);
	color: var(--on-ink);
}
.btn-primary:hover {
	background: var(--ink-muted);
	border-color: var(--ink-muted);
	color: var(--on-ink);
}
.btn-lg {
	height: 48px;
	padding: 0 20px;
	font-size: 15px;
}
.icon-btn {
	display: inline-grid;
	place-items: center;
	width: 36px;
	height: 36px;
	padding: 0;
	border-radius: var(--radius-md);
	border: 1px solid var(--line-strong);
	background: transparent;
	color: var(--ink-muted);
	cursor: pointer;
	transition:
		background-color 0.14s var(--ease),
		color 0.14s var(--ease);
}
.icon-btn:hover {
	color: var(--ink);
	background: var(--fill);
}

/* Hero */
.hero {
	min-height: calc(100vh - 69px);
	padding-block: 64px;
	display: flex;
	flex-wrap: wrap;
	gap: 64px;
	align-items: center;
}
.hero-text {
	flex: 1 1 440px;
	min-width: 0;
	display: flex;
	flex-direction: column;
	gap: 24px;
}
.hero h1 {
	font-size: clamp(40px, 5.6vw, 72px);
	line-height: 1.04;
	letter-spacing: -0.03em;
}
/* The category, for search, in a small line above the slogan */
.kicker {
	display: block;
	margin-bottom: 20px;
	font: 500 16px / 24px var(--font-sans);
	letter-spacing: 0;
	color: var(--ink-muted);
}
.away {
	color: var(--ink-faint);
}
.lead {
	max-width: 36rem;
	font-size: 20px;
	line-height: 30px;
	color: var(--ink-muted);
}
.cta {
	display: flex;
	flex-wrap: wrap;
	gap: 12px;
	align-items: center;
	padding-top: 8px;
}
.install {
	display: inline-flex;
	align-items: center;
	gap: 8px;
	height: 48px;
	padding: 0 4px 0 16px;
	border-radius: var(--radius-md);
	background: var(--surface);
	border: 1px solid var(--line-strong);
}
.install code {
	font-size: 15px;
	color: var(--ink);
}
.install .icon-btn {
	width: 40px;
	height: 40px;
	border: 0;
}
.needs {
	font: 400 13px / 20px var(--font-mono);
	color: var(--ink-faint);
}

/* The window: one card sealed for you, above what was done without you */
.house {
	flex: 1 1 440px;
	min-width: 0;
	max-width: 544px;
	margin: 0;
	display: flex;
	flex-direction: column;
	gap: 12px;
}
.window {
	display: flex;
	flex-direction: column;
	gap: 16px;
	padding: 16px;
	border-radius: var(--radius-xl);
	background: var(--shell);
	border: 1px solid var(--line);
	box-shadow: var(--shadow-float);
}
.window-bar {
	display: flex;
	flex-wrap: wrap;
	gap: 8px;
	align-items: center;
}
.waiting {
	display: inline-flex;
	align-items: center;
	gap: 8px;
	height: 32px;
	padding: 0 12px 0 4px;
	border-radius: var(--radius-pill);
	border: 1px solid var(--accent);
	color: var(--accent);
	font: 500 13px / 1 var(--font-sans);
	white-space: nowrap;
}
.waiting .n {
	display: grid;
	place-items: center;
	min-width: 24px;
	height: 24px;
	padding: 0 4px;
	border-radius: var(--radius-pill);
	background: var(--seal);
	color: var(--on-seal);
	font: 500 12px / 1 var(--font-mono);
}
.pill {
	display: inline-flex;
	align-items: center;
	gap: 8px;
	height: 32px;
	padding: 0 12px;
	border-radius: var(--radius-pill);
	border: 1px solid var(--line);
	background: var(--fill);
	font: 500 13px / 1 var(--font-sans);
	color: var(--ink);
	white-space: nowrap;
}
.pill .meta {
	font: 400 12px / 1 var(--font-mono);
	color: var(--ink-faint);
}
.dot {
	width: 8px;
	height: 8px;
	border-radius: 50%;
	flex: none;
	background: var(--positive);
}
.card {
	display: flex;
	flex-direction: column;
	gap: 16px;
	padding: 20px;
	border-radius: var(--radius-lg);
	background: var(--surface);
	border: 1px solid var(--line);
}
.card .row {
	display: flex;
	flex-wrap: wrap;
	align-items: center;
	gap: 8px;
	font-size: 12px;
	line-height: 16px;
	color: var(--ink-muted);
}
.card .ref {
	font: 400 12px / 1 var(--font-mono);
	color: var(--ink-faint);
}
.card h2 {
	font-size: 20px;
	line-height: 28px;
}
.card .ctx {
	font-size: 15px;
	line-height: 24px;
	color: var(--ink-muted);
}
.card .ctx strong {
	font-weight: 500;
	color: var(--ink);
}
.tag {
	display: inline-flex;
	align-items: center;
	gap: 6px;
	height: 24px;
	padding: 0 8px;
	border-radius: var(--radius-sm);
	background: var(--fill);
	color: var(--ink-muted);
	font: 500 12px / 1 var(--font-sans);
	white-space: nowrap;
}
.tag-kind {
	color: var(--kind-feature);
}
.tag-kind::before {
	content: "";
	width: 6px;
	height: 6px;
	border-radius: 50%;
	background: currentColor;
}
.tag-you {
	background: var(--accent-soft);
	color: var(--accent);
}
.tag-rec {
	background: var(--ink);
	color: var(--on-ink);
}
.options {
	display: grid;
	gap: 8px;
}
.pair {
	display: grid;
	grid-template-columns: repeat(2, minmax(0, 1fr));
	gap: 8px;
}
.option {
	display: flex;
	flex-direction: column;
	gap: 4px;
	padding: 12px 16px;
	border-radius: var(--radius-md);
	border: 1px solid var(--line-strong);
}
.option > b {
	display: inline-flex;
	flex-wrap: wrap;
	align-items: center;
	gap: 8px;
	font: 500 15px / 20px var(--font-sans);
	color: var(--ink);
}
.option > span {
	font-size: 13px;
	line-height: 20px;
	color: var(--ink-muted);
}
.option.rec {
	border-color: var(--ink-muted);
	background: var(--surface-raised);
}
.done {
	display: flex;
	flex-direction: column;
	gap: 8px;
	padding: 0 4px 4px;
	font-size: 13px;
	line-height: 20px;
	color: var(--ink-muted);
}
.done b {
	font-weight: 500;
	color: var(--ink);
}
.done ul {
	margin: 0;
	padding: 0;
	list-style: none;
	display: grid;
	gap: 4px;
}
.done time {
	display: inline-block;
	width: 48px;
	font: 400 12px / 20px var(--font-mono);
	color: var(--ink-faint);
}
.house figcaption {
	font: 400 12px / 16px var(--font-mono);
	color: var(--ink-faint);
	text-align: right;
}

/* 留守番 */
.word {
	padding-block: 40px;
	display: flex;
	flex-wrap: wrap;
	gap: 12px 24px;
	align-items: baseline;
	justify-content: center;
	text-align: center;
}
.word span {
	font: 500 40px / 1 var(--font-display);
	color: var(--ink);
}
.word p {
	font-size: 18px;
	line-height: 28px;
	color: var(--ink-muted);
}

/* How it works */
.steps {
	margin: 0;
	padding: 0;
	list-style: none;
	display: grid;
	gap: 12px;
	grid-template-columns: repeat(auto-fit, minmax(min(100%, 192px), 1fr));
}
.step {
	display: flex;
	flex-direction: column;
	align-items: flex-start;
	gap: 8px;
	padding: 20px;
	border-radius: var(--radius-lg);
	background: var(--surface);
	border: 1px solid var(--line);
}
.step .n {
	font: 400 12px / 16px var(--font-mono);
	color: var(--ink-faint);
}
.step h3 {
	font-size: 20px;
	line-height: 28px;
}
.step p {
	font-size: 15px;
	line-height: 24px;
	color: var(--ink-muted);
	padding-bottom: 8px;
}
.step .tag {
	margin-top: auto;
}
.step.you {
	border-color: var(--accent);
}
.rules {
	display: flex;
	flex-wrap: wrap;
	gap: 32px 48px;
	align-items: flex-start;
}
.rules > div {
	flex: 1 1 320px;
	display: flex;
	flex-direction: column;
	gap: 12px;
}
.rules h3 {
	font-size: 24px;
	line-height: 32px;
}
.rules figure {
	flex: 1 1 480px;
	min-width: 0;
	margin: 0;
	border-radius: var(--radius-lg);
	background: var(--surface);
	border: 1px solid var(--line);
	overflow: hidden;
}
.rules figcaption {
	padding: 12px 16px;
	font: 400 13px / 20px var(--font-mono);
	color: var(--ink-faint);
	border-bottom: 1px solid var(--line);
}
.rules pre {
	margin: 0;
	padding: 16px;
	overflow-x: auto;
	font: 400 14px / 24px var(--font-mono);
	color: var(--ink);
}

/* Agents never merge */
.locks {
	padding-block: 96px;
	display: flex;
	flex-wrap: wrap;
	gap: 48px 64px;
	align-items: center;
}
.locks > div {
	flex: 1 1 380px;
	display: flex;
	flex-direction: column;
	gap: 16px;
}
.gates {
	flex: 1 1 420px;
	margin: 0;
	padding: 0;
	list-style: none;
	display: grid;
	gap: 8px;
	grid-template-columns: repeat(auto-fit, minmax(min(100%, 200px), 1fr));
}
.gates li {
	display: flex;
	align-items: center;
	gap: 12px;
	min-height: 44px;
	padding: 12px 16px;
	border-radius: var(--radius-md);
	background: var(--surface);
	border: 1px solid var(--line);
	font-size: 15px;
	line-height: 20px;
}
.gates li::before {
	content: "";
	width: 8px;
	height: 8px;
	flex: none;
	border-radius: 2px;
	background: var(--positive);
}

/* What you get: a quiet list, not a wall of cards */
.features {
	margin: 0;
	display: grid;
	gap: 0 48px;
	grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr));
}
.features div {
	padding-block: 20px;
	border-top: 1px solid var(--line);
	display: flex;
	flex-direction: column;
	gap: 4px;
}
.features dt {
	font: 500 17px / 24px var(--font-display);
	color: var(--ink);
}
.features dd {
	margin: 0;
	font-size: 15px;
	line-height: 24px;
	color: var(--ink-muted);
}

/* Get started */
.start {
	margin: 0;
	padding: 0;
	list-style: none;
	display: grid;
	gap: 32px;
	grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
}
.start li {
	display: flex;
	flex-direction: column;
	gap: 12px;
}
.start li > span {
	font: 500 17px / 24px var(--font-display);
	color: var(--ink);
}
.start code {
	display: block;
	font-size: 14px;
	line-height: 20px;
	color: var(--ink);
	background: var(--surface);
	border: 1px solid var(--line);
	border-radius: var(--radius-md);
	padding: 12px 16px;
}
.start p {
	font-size: 15px;
	line-height: 24px;
	color: var(--ink-muted);
}

/* Footer: every page one click away */
.foot {
	border-top: 1px solid var(--line);
}
.foot-inner {
	padding-block: 48px;
	display: flex;
	flex-wrap: wrap;
	gap: 32px 64px;
}
.foot-brand {
	flex: 1 1 240px;
	display: flex;
	flex-direction: column;
	gap: 12px;
	font-size: 14px;
	line-height: 22px;
	color: var(--ink-muted);
}
.foot .brand {
	font-size: 16px;
}
.foot-cols {
	flex: 3 1 560px;
	display: grid;
	gap: 32px;
	grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
}
.foot-cols p {
	font: 500 14px / 20px var(--font-sans);
	color: var(--ink);
}
.foot-cols ul {
	margin: 8px 0 0;
	padding: 0;
	list-style: none;
	display: grid;
	gap: 8px;
}

/* Pages set for reading: the docs, the features and the comparisons */
.page {
	padding-block: 64px 96px;
}
.prose {
	max-width: 760px;
	min-width: 0;
}
.prose > * + * {
	margin-top: 16px;
}
.prose h1 {
	font-size: 40px;
	line-height: 48px;
	letter-spacing: -0.02em;
}
.prose h2 {
	margin-top: 48px;
	font-size: 28px;
	line-height: 36px;
	letter-spacing: -0.01em;
}
.prose h3 {
	margin-top: 32px;
	font-size: 20px;
	line-height: 28px;
}
.prose h2 + *,
.prose h3 + * {
	margin-top: 12px;
}
.prose ul,
.prose ol {
	margin-bottom: 0;
	padding-left: 24px;
}
.prose li + li {
	margin-top: 8px;
}
.prose li > ul,
.prose li > ol {
	margin-top: 8px;
}
.prose code {
	font-size: 0.875em;
	padding: 2px 4px;
	border-radius: var(--radius-xs);
	background: var(--fill);
}
.prose pre {
	margin-bottom: 0;
	padding: 16px;
	overflow-x: auto;
	tab-size: 2;
	border-radius: var(--radius-md);
	background: var(--surface);
	border: 1px solid var(--line);
	font: 400 14px / 22px var(--font-mono);
}
.prose pre code {
	padding: 0;
	background: none;
	font-size: inherit;
}
.prose .table {
	overflow-x: auto;
	border: 1px solid var(--line);
	border-radius: var(--radius-md);
}
.prose table {
	width: 100%;
	border-collapse: collapse;
	font-size: 14px;
	line-height: 22px;
}
.prose th,
.prose td {
	padding: 8px 12px;
	text-align: left;
	vertical-align: top;
	border-bottom: 1px solid var(--line);
}
.prose th {
	font-weight: 500;
	background: var(--shell);
}
.prose tr:last-child td {
	border-bottom: 0;
}
.prose .lede {
	font-size: 18px;
	line-height: 28px;
	color: var(--ink-muted);
}
.prose .note {
	font-size: 14px;
	line-height: 22px;
	color: var(--ink-faint);
}

/* Docs: the menu beside the page */
.doc {
	display: grid;
	grid-template-columns: 200px minmax(0, 1fr);
	gap: 48px;
	align-items: start;
}
.doc-nav {
	position: sticky;
	top: 24px;
}

@media (max-width: 860px) {
	.doc {
		grid-template-columns: minmax(0, 1fr);
	}
	.doc-nav {
		position: static;
		order: 2;
		padding-top: 24px;
		border-top: 1px solid var(--line);
	}
}
@media (max-width: 640px) {
	.wrap {
		padding-left: max(16px, env(safe-area-inset-left, 0px));
		padding-right: max(16px, env(safe-area-inset-right, 0px));
	}
	.top .links a:not(.btn) {
		display: none;
	}
	.hero {
		min-height: 0;
		padding-block: 48px;
		gap: 40px;
	}
	.section,
	.locks {
		padding-block: 64px;
	}
	.section h2,
	.locks h2 {
		font-size: 28px;
		line-height: 36px;
	}
	.mark {
		font-size: 28px;
	}
	.pair {
		grid-template-columns: 1fr;
	}
	.done {
		display: none;
	}
	.page {
		padding-block: 40px 64px;
	}
	.prose h1 {
		font-size: 32px;
		line-height: 40px;
	}
	.prose h2 {
		font-size: 24px;
		line-height: 32px;
	}
}
@media (prefers-reduced-motion: reduce) {
	.btn,
	.icon-btn,
	.top .links a:not(.btn) {
		transition: none;
	}
}