:root {
	--paper: #f6f5f0;
	--surface: #ffffff;
	--ink: #17191a;
	--ink-2: #3c4043;
	--muted: #6b6f72;
	--rule: #e3e0d8;
	--rule-2: #d6d2c8;
	--accent: #0a7564;
	--accent-ink: #075a4d;
	--accent-soft: #e2f1ec;
	--code-bg: #0f1514;
	--code-ink: #d8e4e1;
	--code-bar: #1a2321;
	--inline-code: #ecebe4;
	--serif: 'Newsreader', Georgia, serif;
	--sans: 'IBM Plex Sans', system-ui, sans-serif;
	--mono: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, monospace;
	--side: 244px;
	--toc: 208px;
	--read: 720px;
	color-scheme: light;
}
@media (prefers-color-scheme: dark) {
	:root {
		--paper: #0b100f;
		--surface: #101817;
		--ink: #e6eeec;
		--ink-2: #c3d0cd;
		--muted: #8a9e9a;
		--rule: #1c2826;
		--rule-2: #273634;
		--accent: #8ff5dc;
		--accent-ink: #8ff5dc;
		--accent-soft: #11241f;
		--code-bg: #070b0a;
		--code-ink: #d8e4e1;
		--code-bar: #0f1716;
		--inline-code: #16211f;
		color-scheme: dark;
	}
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: 76px; }
body {
	margin: 0;
	background: var(--paper);
	color: var(--ink);
	font: 16px/1.65 var(--sans);
	-webkit-font-smoothing: antialiased;
	text-rendering: optimizeLegibility;
}
a { color: var(--accent-ink); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
::selection { background: var(--accent-soft); }

/* header */
.top {
	position: sticky; top: 0; z-index: 20;
	display: flex; align-items: center; gap: 16px;
	height: 60px; padding: 0 24px;
	background: color-mix(in srgb, var(--paper) 88%, transparent);
	backdrop-filter: saturate(1.4) blur(10px);
	border-bottom: 1px solid var(--rule);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-weight: 600; letter-spacing: -.01em; }
.brand svg { width: 22px; height: 22px; fill: none; stroke: var(--accent); stroke-width: 1.8; stroke-linecap: round; }
.brand em { font: 500 12px var(--mono); font-style: normal; color: var(--muted); border: 1px solid var(--rule-2); border-radius: 5px; padding: 1px 6px; }
.links { margin-left: auto; display: flex; align-items: center; gap: 22px; font-size: 14px; }
.links a { color: var(--ink-2); text-decoration: none; }
.links a:hover { color: var(--ink); }
.links .pill { font: 500 12.5px var(--mono); border: 1px solid var(--rule-2); padding: 4px 10px; border-radius: 999px; color: var(--ink); }
.links .pill:hover { border-color: var(--accent); }
.menu { display: none; }

/* layout */
.shell { display: grid; grid-template-columns: var(--side) minmax(0, 1fr) var(--toc); max-width: 1320px; margin: 0 auto; }
.side, .toc { position: sticky; top: 60px; align-self: start; height: calc(100vh - 60px); overflow-y: auto; }
.side { padding: 28px 16px 24px 24px; border-right: 1px solid var(--rule); display: flex; flex-direction: column; }
.side ul, .toc ul { list-style: none; margin: 0; padding: 0; }
.side li a {
	display: block; padding: 6px 12px; margin: 1px 0; border-radius: 8px;
	color: var(--ink-2); text-decoration: none; font-size: 14.5px;
}
.side li a:hover { background: color-mix(in srgb, var(--rule) 60%, transparent); color: var(--ink); }
.side li a[aria-current] { background: var(--accent-soft); color: var(--accent-ink); font-weight: 500; }
.side-foot { margin-top: auto; padding: 16px 12px 0; display: flex; gap: 14px; font: 12.5px var(--mono); }
.side-foot a { color: var(--muted); text-decoration: none; }
.side-foot a:hover { color: var(--ink); }
.toc { padding: 36px 24px 24px 20px; font-size: 13px; }
.toc p { margin: 0 0 10px; font: 500 11px var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
.toc li a { display: block; padding: 4px 0 4px 12px; border-left: 1px solid var(--rule); color: var(--muted); text-decoration: none; line-height: 1.4; }
.toc li.d3 a { padding-left: 24px; }
.toc li a:hover { color: var(--ink); }
.toc li a.on { color: var(--accent-ink); border-left-color: var(--accent); }
main { min-width: 0; padding: 44px 56px 96px; }

/* article */
.doc { max-width: var(--read); margin: 0 auto; }
.doc h1 { font: 500 42px/1.12 var(--serif); letter-spacing: -.02em; margin: 0 0 20px; text-wrap: balance; }
.home .doc h1 { font-size: 52px; max-width: 16ch; }
.doc h1 + p { font-size: 18.5px; line-height: 1.6; color: var(--ink-2); }
.doc h2 { font: 500 27px/1.25 var(--serif); letter-spacing: -.01em; margin: 56px 0 14px; padding-top: 20px; border-top: 1px solid var(--rule); position: relative; }
.doc h3 { font-size: 17px; font-weight: 600; margin: 32px 0 8px; position: relative; }
.doc h2 .anchor, .doc h3 .anchor { position: absolute; left: -22px; color: var(--rule-2); text-decoration: none; opacity: 0; font-weight: 400; }
.doc h2 .anchor { top: 22px; }
.doc h2:hover .anchor, .doc h3:hover .anchor { opacity: 1; }
.doc p { margin: 0 0 16px; }
.doc ul, .doc ol { padding-left: 22px; margin: 0 0 18px; }
.doc li { margin: 5px 0; }
.doc li::marker { color: var(--muted); }
.doc strong { font-weight: 600; }
.doc code { font: .87em var(--mono); background: var(--inline-code); padding: .12em .38em; border-radius: 5px; overflow-wrap: anywhere; }
.doc a code { color: inherit; }
.doc a.ext::after { content: '↗'; font-size: .75em; margin-left: 2px; color: var(--muted); }

/* code blocks */
.code { margin: 20px 0 24px; border-radius: 12px; overflow: hidden; background: var(--code-bg); border: 1px solid color-mix(in srgb, var(--code-bg) 70%, var(--rule)); }
.code figcaption { display: flex; justify-content: space-between; align-items: center; padding: 7px 10px 7px 16px; background: var(--code-bar); font: 500 11.5px var(--mono); color: #7f928e; letter-spacing: .03em; }
.code .copy { font: 500 11.5px var(--mono); color: #b9cac6; background: transparent; border: 1px solid #2c3a37; border-radius: 6px; padding: 3px 9px; cursor: pointer; }
.code .copy:hover { color: #fff; border-color: #4a605b; }
.code pre { margin: 0; padding: 16px 18px 18px; overflow-x: auto; }
.code code { font: 13.5px/1.7 var(--mono); color: var(--code-ink); background: none; padding: 0; tab-size: 2; }
.code .k { color: #f0a6ca; }
.code .s { color: #9fe3b4; }
.code .n { color: #f5c983; }
.code .c { color: #6f817d; font-style: italic; }
.code .f { color: #8fd0ff; }
.code .t { color: #c6b8ff; }

/* tables */
.table { overflow-x: auto; margin: 18px 0 26px; border: 1px solid var(--rule); border-radius: 12px; background: var(--surface); }
.doc table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.doc th { text-align: left; font: 500 11.5px var(--mono); letter-spacing: .06em; text-transform: uppercase; color: var(--muted); padding: 10px 16px; border-bottom: 1px solid var(--rule); background: color-mix(in srgb, var(--paper) 55%, var(--surface)); }
.doc td { padding: 11px 16px; border-bottom: 1px solid var(--rule); vertical-align: top; }
.doc tr:last-child td { border-bottom: 0; }
.doc td:first-child { color: var(--ink); white-space: nowrap; }
.doc td code { font-size: .82em; white-space: nowrap; }
.doc td:first-child code { background: none; padding: 0; }
.doc td:nth-child(2) code { white-space: normal; overflow-wrap: anywhere; }

/* notes */
.doc .note { margin: 18px 0 24px; padding: 13px 16px; border-left: 3px solid var(--accent); background: var(--accent-soft); border-radius: 0 10px 10px 0; font-size: 15px; color: var(--ink-2); }

/* home: cards */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin: 30px 0 8px; }
.card { display: flex; flex-direction: column; gap: 6px; padding: 16px 18px 18px; border: 1px solid var(--rule); border-radius: 12px; background: var(--surface); color: var(--ink); text-decoration: none; transition: border-color .15s, transform .15s; }
.card:hover { border-color: var(--accent); transform: translateY(-1px); }
.card b { font-weight: 600; font-size: 15px; }
.card b::after { content: ' →'; color: var(--accent); }
.card span { font-size: 13.5px; line-height: 1.5; color: var(--muted); }

/* home: the Buy timeline */
.doc ol.rail { list-style: none; padding: 0; margin: 22px 0 10px; }
.rail li { display: grid; grid-template-columns: 96px 1fr; column-gap: 36px; margin: 0; padding: 0 0 22px; position: relative; color: var(--ink-2); font-size: 15px; }
.rail li::before { content: ''; position: absolute; left: 108px; top: 8px; width: 11px; height: 11px; border-radius: 50%; background: var(--paper); border: 2px solid var(--accent); box-sizing: border-box; }
.rail li:not(:last-child)::after { content: ''; position: absolute; left: 113px; top: 22px; bottom: 2px; width: 1px; background: var(--rule-2); }
.rail li:last-child::before { background: var(--accent); }
.rail .t { grid-row: span 2; text-align: right; font: 500 13px/1.9 var(--mono); color: var(--accent-ink); white-space: nowrap; }
.rail b { display: block; color: var(--ink); font-weight: 600; }

/* page foot */
.page-tools { display: flex; gap: 16px; align-items: center; margin: 56px 0 18px; font: 13px var(--mono); }
.page-tools a { color: var(--muted); text-decoration: none; }
.page-tools a:hover { color: var(--ink); }
.page-tools button { font: 13px var(--mono); color: var(--muted); background: none; border: 1px solid var(--rule-2); border-radius: 7px; padding: 4px 10px; cursor: pointer; }
.page-tools button:hover { color: var(--ink); border-color: var(--accent); }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.pager a { display: flex; flex-direction: column; padding: 14px 18px; border: 1px solid var(--rule); border-radius: 12px; text-decoration: none; color: var(--ink); font-weight: 500; background: var(--surface); }
.pager a:hover { border-color: var(--accent); }
.pager small { font: 500 11px var(--mono); letter-spacing: .06em; text-transform: uppercase; color: var(--muted); margin-bottom: 2px; }
.pager .next { text-align: right; grid-column: 2; }

/* responsive */
@media (max-width: 1180px) {
	.shell { grid-template-columns: var(--side) minmax(0, 1fr); }
	.toc { display: none; }
}
@media (max-width: 860px) {
	.shell { display: block; }
	.menu { display: grid; place-items: center; width: 36px; height: 36px; margin-left: -8px; border: 0; background: none; cursor: pointer; }
	.menu span, .menu span::before, .menu span::after { display: block; width: 18px; height: 1.5px; background: var(--ink); position: relative; content: ''; transition: transform .2s; }
	.menu span::before { position: absolute; top: -6px; }
	.menu span::after { position: absolute; top: 6px; }
	.side { position: fixed; inset: 60px 0 0 0; z-index: 15; background: var(--paper); height: auto; border: 0; transform: translateX(-100%); transition: transform .2s ease; padding: 20px; }
	body.nav-open .side { transform: none; }
	.links a:not(.pill) { display: none; }
	main { padding: 32px 20px 72px; }
	.doc h1, .home .doc h1 { font-size: 34px; }
	.cards { grid-template-columns: 1fr; }
	.rail li { grid-template-columns: 72px 1fr; column-gap: 32px; }
	.rail li::before { left: 82px; }
	.rail li:not(:last-child)::after { left: 87px; }
	.doc h2 .anchor, .doc h3 .anchor { display: none; }
}