:root {
	color-scheme: light;
	--sumi: #15231d;
	--ink-soft: #53615a;
	--paper: #f6f8f5;
	--rule: #cbd4ce;
	--vermilion: #b84232;
	--moss: #315f4d;
	--mist: #dfe9e3;
}

* {
	box-sizing: border-box;
}

body {
	margin: 0;
	background: var(--paper);
	color: var(--sumi);
	font-family: "Avenir Next", Avenir, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
	line-height: 1.65;
}

main {
	width: min(980px, calc(100% - 36px));
	margin: 0 auto;
	padding: 72px 0 96px;
}

.masthead {
	display: grid;
	grid-template-columns: minmax(0, 1fr) auto;
	gap: 48px;
	align-items: end;
	padding-bottom: 38px;
	border-bottom: 3px solid var(--sumi);
}

h1,
h2,
p {
	margin-top: 0;
}

h1 {
	max-width: 13ch;
	margin-bottom: 18px;
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: clamp(3rem, 9vw, 6.8rem);
	font-weight: 500;
	letter-spacing: -0.055em;
	line-height: 0.98;
}

.intro {
	max-width: 55ch;
	margin-bottom: 0;
	color: var(--ink-soft);
	font-size: 1.05rem;
}

.seal {
	display: grid;
	width: 92px;
	height: 92px;
	place-items: center;
	border: 2px solid var(--vermilion);
	color: var(--vermilion);
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: 2.6rem;
	line-height: 1;
	writing-mode: vertical-rl;
}

.tracks {
	display: grid;
	grid-template-columns: repeat(2, minmax(0, 1fr));
	gap: 0 56px;
}

.track {
	padding-top: 38px;
}

.track-heading {
	display: flex;
	align-items: baseline;
	justify-content: space-between;
	gap: 16px;
	margin-bottom: 14px;
}

h2 {
	margin-bottom: 0;
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: 1.8rem;
	font-weight: 600;
}

.duration {
	color: var(--ink-soft);
	font-size: 0.82rem;
}

.description {
	min-height: 5.25em;
	color: var(--ink-soft);
}

.lesson-list {
	margin: 0;
	padding: 0;
	border-top: 1px solid var(--rule);
	list-style: none;
}

.lesson-order {
	display: flex;
	justify-content: space-between;
	align-items: center;
	gap: 16px;
	margin-top: 25px;
	padding-bottom: 12px;
	color: var(--ink-soft);
	font-size: 0.82rem;
}

.lesson-order button {
	border: 1px solid var(--rule);
	padding: 6px 10px;
	background: transparent;
	color: var(--moss);
	font: inherit;
	cursor: pointer;
}

.lesson-order button:focus-visible {
	outline: 2px solid var(--moss);
	outline-offset: 3px;
}

.lesson-list li {
	border-bottom: 1px solid var(--rule);
}

.lesson-list a {
	display: grid;
	grid-template-columns: 3.5rem minmax(0, 1fr) auto;
	gap: 15px;
	align-items: baseline;
	padding: 18px 4px;
	color: inherit;
	text-decoration: none;
}

.lesson-list a:hover .title,
.lesson-list a:focus-visible .title {
	color: var(--vermilion);
}

.lesson-list a:focus-visible {
	outline: 3px solid var(--mist);
	outline-offset: 3px;
}

.number {
	color: var(--vermilion);
	font-variant-numeric: tabular-nums;
	font-weight: 700;
}

.title {
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: 1.13rem;
}

.topic {
	color: var(--moss);
	font-size: 0.82rem;
}

.methods {
	margin-top: 72px;
	padding-top: 34px;
	border-top: 3px solid var(--sumi);
}

.methods-intro {
	display: grid;
	grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
	gap: 56px;
	align-items: start;
	margin-bottom: 28px;
}

.methods-intro p {
	max-width: 57ch;
	margin-bottom: 0;
	color: var(--ink-soft);
}

.method {
	margin-top: 28px;
	border-bottom: 1px solid var(--rule);
}

.method:first-of-type {
	border-top: 1px solid var(--rule);
}

.method > summary {
	display: grid;
	grid-template-columns: minmax(0, 1fr) 1.5rem;
	gap: 28px;
	align-items: center;
	padding: 24px 4px;
	cursor: pointer;
	list-style: none;
}

.method > summary::-webkit-details-marker,
.prompt-disclosure > summary::-webkit-details-marker {
	display: none;
}

.method > summary:focus-visible,
.prompt-disclosure > summary:focus-visible {
	outline: 3px solid var(--mist);
	outline-offset: 4px;
}

.method-summary-copy {
	display: grid;
	gap: 3px;
}

.method-kind {
	color: var(--vermilion);
	font-size: 0.82rem;
	font-weight: 700;
}

.method-summary-copy strong {
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: clamp(1.2rem, 3vw, 1.5rem);
	font-weight: 600;
	line-height: 1.3;
}

.method-accent {
	color: var(--vermilion);
}

.method-meta {
	display: flex;
	grid-column: 1;
	grid-row: 2;
	gap: 14px;
	color: var(--ink-soft);
	font-size: 0.78rem;
	text-align: left;
}

.disclosure-mark {
	grid-column: 2;
	grid-row: 1 / span 2;
}

.disclosure-mark::before {
	content: "+";
	color: var(--moss);
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: 1.5rem;
	line-height: 1;
}

.method[open] > summary .disclosure-mark::before {
	content: "−";
}

.method-body {
	padding: 8px 4px 42px;
}

.method-goal {
	display: grid;
	grid-template-columns: minmax(0, 0.8fr) minmax(0, 3.2fr);
	gap: 28px;
	margin-bottom: 28px;
}

.method-body h3,
.method-body h4 {
	margin: 0;
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-weight: 600;
}

.method-body h3 {
	font-size: 1.12rem;
}

.method-body h4 {
	font-size: 1.02rem;
}

.method-goal p {
	max-width: 65ch;
	margin-bottom: 0;
	font-size: 1.03rem;
}

.process-grid {
	display: grid;
	grid-template-columns: repeat(2, minmax(0, 1fr));
	margin: 0;
	padding: 0;
	border-top: 1px solid var(--rule);
	border-bottom: 1px solid var(--rule);
	list-style: none;
}

.process-grid li {
	min-width: 0;
	padding: 20px 18px 22px;
	border-left: 1px solid var(--rule);
}

.process-grid li:first-child {
	border-left: 0;
}

.process-grid li:nth-child(3) {
	border-left: 0;
	border-top: 1px solid var(--rule);
}

.process-grid li:nth-child(4) {
	border-top: 1px solid var(--rule);
}

.step-heading {
	display: flex;
	justify-content: space-between;
	gap: 8px;
	margin-bottom: 13px;
}

.step-number {
	color: var(--vermilion);
	font-weight: 700;
	font-variant-numeric: tabular-nums;
}

.step-time {
	color: var(--ink-soft);
	font-size: 0.75rem;
}

.process-grid p {
	margin: 8px 0 0;
	color: var(--ink-soft);
	font-size: 0.88rem;
	line-height: 1.55;
}

.constants {
	display: grid;
	grid-template-columns: minmax(0, 0.8fr) minmax(0, 3.2fr);
	gap: 28px;
	padding: 30px 0;
}

.constants ul {
	display: grid;
	grid-template-columns: repeat(2, minmax(0, 1fr));
	gap: 10px 30px;
	margin: 0;
	padding-left: 1.15rem;
}

.constants li::marker {
	color: var(--vermilion);
}

.prompt-disclosure {
	border-top: 1px solid var(--moss);
	border-bottom: 1px solid var(--moss);
	background: var(--mist);
}

.prompt-disclosure > summary {
	position: relative;
	padding: 18px 48px 18px 20px;
	cursor: pointer;
	color: var(--moss);
	font-weight: 700;
	list-style: none;
}

.prompt-disclosure > summary::after {
	position: absolute;
	top: 50%;
	right: 20px;
	content: "+";
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-size: 1.35rem;
	font-weight: 400;
	transform: translateY(-50%);
}

.prompt-disclosure[open] > summary::after {
	content: "−";
}

.prompt-panel {
	padding: 0 20px 22px;
}

.prompt-toolbar {
	display: flex;
	justify-content: space-between;
	gap: 24px;
	align-items: center;
	padding-top: 18px;
	border-top: 1px solid color-mix(in srgb, var(--moss) 32%, transparent);
}

.prompt-toolbar p {
	max-width: 55ch;
	margin-bottom: 0;
	color: var(--ink-soft);
	font-size: 0.88rem;
}

.copy-action {
	display: flex;
	align-items: center;
	gap: 12px;
	flex-shrink: 0;
}

.copy-action button {
	appearance: none;
	padding: 9px 13px;
	border: 1px solid var(--moss);
	background: var(--moss);
	color: white;
	cursor: pointer;
	font: 700 0.82rem "Avenir Next", Avenir, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
}

.copy-action button:hover {
	background: transparent;
	color: var(--moss);
}

.copy-action button:focus-visible {
	outline: 3px solid white;
	outline-offset: -5px;
}

.copy-status {
	max-width: 14rem;
	color: var(--moss);
	font-size: 0.78rem;
}

.prompt-panel pre {
	max-height: 30rem;
	margin: 18px 0 0;
	padding: 20px;
	overflow: auto;
	border: 1px solid var(--rule);
	background: var(--paper);
	white-space: pre-wrap;
	word-break: normal;
	font: 0.84rem/1.62 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

.prompt-panel pre:focus-visible {
	outline: 3px solid var(--moss);
	outline-offset: 2px;
}

footer {
	display: flex;
	justify-content: space-between;
	gap: 20px;
	margin-top: 64px;
	padding-top: 18px;
	border-top: 1px solid var(--rule);
	color: var(--ink-soft);
	font-size: 0.84rem;
}

footer a {
	color: inherit;
	overflow-wrap: anywhere;
}

@media (max-width: 720px) {
	main {
		padding-top: 40px;
	}
	.masthead {
		grid-template-columns: 1fr;
		gap: 24px;
	}
	.seal {
		width: 68px;
		height: 68px;
		font-size: 2rem;
	}
	.tracks {
		grid-template-columns: 1fr;
	}
	.methods {
		margin-top: 54px;
	}
	.methods-intro,
	.method-goal,
	.constants {
		grid-template-columns: 1fr;
		gap: 10px;
	}
	.method > summary {
		grid-template-columns: minmax(0, 1fr) 1.5rem;
		gap: 16px;
	}
	.method-meta {
		display: flex;
		grid-column: 1;
		grid-row: 2;
		gap: 14px;
		text-align: left;
	}
	.disclosure-mark {
		grid-column: 2;
		grid-row: 1 / span 2;
		align-self: center;
	}
	.process-grid {
		grid-template-columns: repeat(2, minmax(0, 1fr));
	}
	.process-grid li:nth-child(3) {
		border-left: 0;
		border-top: 1px solid var(--rule);
	}
	.process-grid li:nth-child(4) {
		border-top: 1px solid var(--rule);
	}
	.constants ul {
		grid-template-columns: 1fr;
	}
	.prompt-toolbar {
		align-items: flex-start;
		flex-direction: column;
	}
	.description {
		min-height: 0;
	}
	.lesson-list a {
		grid-template-columns: 3.25rem minmax(0, 1fr);
	}
	.topic {
		grid-column: 2;
	}
	footer {
		flex-direction: column;
	}
}

@media (max-width: 480px) {
	.process-grid {
		grid-template-columns: 1fr;
	}
	.process-grid li,
	.process-grid li:nth-child(3) {
		border-top: 1px solid var(--rule);
		border-left: 0;
	}
	.process-grid li:first-child {
		border-top: 0;
	}
	.prompt-panel {
		padding-right: 14px;
		padding-left: 14px;
	}
}

@media (prefers-reduced-motion: no-preference) {
	.title {
		transition: color 140ms ease;
	}
}