:root { color-scheme: light dark; --ink: #e8edf2; --muted: #a2adb7; --line: #2d3841; --paper: #12171c; --panel: #10151a; --rail: #0e1318; --accent: #72b5e2; --soft: #202a32; }
:root[data-theme="dark"] { color-scheme: dark; }
:root[data-theme="light"] { color-scheme: light; }
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) { --ink: #26313a; --muted: #60707d; --line: #cbd5dc; --paper: #f7f9fa; --panel: #ffffff; --rail: #eef3f6; --accent: #176b9f; --soft: #e7edf1; }
}
:root[data-theme="light"] { --ink: #26313a; --muted: #60707d; --line: #cbd5dc; --paper: #f7f9fa; --panel: #ffffff; --rail: #eef3f6; --accent: #176b9f; --soft: #e7edf1; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font-family: Courier, "Courier New", ui-monospace, SFMono-Regular, Menlo, monospace; line-height: 1.62; }
a { color: var(--accent); text-underline-offset: .18em; }
article a { padding-inline: .1em; text-decoration-thickness: 1px; }
a:focus-visible, button:focus-visible { outline: 3px solid #d39a38; outline-offset: 4px; }
.skip-link { position: absolute; left: 1rem; top: -5rem; background: var(--ink); color: white; padding: .5rem 1rem; z-index: 10; }
.skip-link:focus { top: 1rem; }
.site-header { height: 5.25rem; border-bottom: 1px solid var(--line); padding: 0 clamp(1rem, 3vw, 2.4rem); display: flex; align-items: center; background: var(--panel); position: sticky; top: 0; z-index: 5; }
.brand { display: flex; align-items: center; gap: .8rem; color: var(--ink); text-decoration: none; }
.brand-logo { width: 2.9rem; height: 2.9rem; object-fit: contain; }
.brand strong, .brand span { display: block; letter-spacing: .11em; font-size: .78rem; }
.brand span { color: var(--muted); font-size: .63rem; letter-spacing: .05em; }
.site-layout { display: grid; grid-template-columns: 18rem minmax(0, 1fr); min-height: calc(100vh - 5.25rem); }
.site-rail { background: var(--rail); border-right: 1px solid var(--line); padding: 2rem 1.2rem; position: sticky; top: 5.25rem; height: calc(100vh - 5.25rem); overflow-y: auto; }
.rail-label { margin: 0 0 1.2rem; color: var(--muted); font-size: .68rem; font-weight: 700; letter-spacing: .12em; }
nav { display: grid; gap: .15rem; }
nav a { color: var(--muted); font-size: .82rem; text-decoration: none; padding: .55rem .7rem; border-bottom: 1px solid transparent; }
nav a:hover, nav a.active { color: var(--accent); text-decoration: underline; }
.header-actions { display: flex; align-items: center; gap: .6rem; margin-left: auto; }
.theme-toggle, .nav-toggle { border: 1px solid var(--line); background: transparent; padding: .45rem .7rem; color: var(--ink); font: inherit; font-size: .7rem; cursor: pointer; }
.theme-toggle:hover, .nav-toggle:hover { border-color: var(--accent); color: var(--accent); }
.nav-toggle { display: none; }
.page { width: min(58rem, calc(100% - 3rem)); margin: 0 auto; padding: clamp(3rem, 8vw, 7rem) 0; min-height: 70vh; }
.chapter-pager { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: stretch; gap: 1rem; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); margin: 0 0 3rem; }
.chapter-pager:last-child { margin: 4rem 0 0; }
.chapter-pager-link { display: flex; align-items: center; gap: .8rem; min-width: 0; padding: 1rem 0; color: var(--muted); text-decoration: none; font-size: .78rem; }
.chapter-pager-link:hover { color: var(--accent); }
.chapter-pager-link span:nth-child(2) { min-width: 0; }
.chapter-pager-link small { display: block; color: var(--accent); font-size: .62rem; letter-spacing: .12em; margin-bottom: .25rem; }
.chapter-pager-next { justify-content: flex-end; text-align: right; }
.chapter-pager-position { align-self: center; color: var(--muted); font-size: .68rem; letter-spacing: .12em; white-space: nowrap; }
.chapter-pager-placeholder { min-width: 1rem; }
.eyebrow { color: var(--muted); font-size: .78rem; letter-spacing: .1em; text-transform: uppercase; margin-bottom: 3rem; }
article { max-width: 52rem; }
.home-feature { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(20rem, .95fr); gap: clamp(2rem, 6vw, 5rem); align-items: center; margin: 0 0 5rem; padding-bottom: 3rem; border-bottom: 1px solid var(--line); }
.home-feature-copy { min-width: 0; }
.feature-kicker { color: var(--muted); font-size: .68rem; font-weight: 700; letter-spacing: .16em; margin: 0 0 1.2rem; }
.home-feature h1 { font-size: clamp(2.45rem, 4.4vw, 4rem); max-width: 10ch; margin: 0 0 1.3rem; }
.feature-lead { color: var(--muted); font-size: clamp(1rem, 1.5vw, 1.25rem); line-height: 1.5; max-width: 36rem; margin: 0; }
.system-figure { margin: 0; }
.system-figure img { display: block; width: 100%; height: auto; border: 1px solid var(--line); }
.system-figure figcaption { color: var(--muted); font-size: .68rem; margin-top: .6rem; }
.state-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .65rem; margin-top: 2rem; }
.state-grid div { border-top: 1px solid var(--line); padding-top: .65rem; }
.state-grid strong, .state-grid span { display: block; }
.state-grid strong { color: var(--ink); font-size: .78rem; }
.state-grid span { color: var(--muted); font-size: .72rem; margin-top: .15rem; }
h1, h2, h3 { color: var(--ink); line-height: 1.2; letter-spacing: -.015em; }
h1 { font-size: clamp(2.35rem, 5vw, 4.35rem); line-height: 1.12; margin: 0 0 1.8rem; letter-spacing: -.02em; max-width: 11ch; }
h2 { font-size: clamp(1.3rem, 3vw, 2rem); margin-top: 3rem; border-top: 1px solid var(--line); padding-top: 1rem; }
p, ul, ol { margin: 1.25rem 0; }
li { margin: .45rem 0; }
code { background: var(--soft); padding: .12em .3em; }
.site-footer { border-top: 1px solid var(--line); padding: 2.5rem clamp(1rem, 5vw, 5rem) 2rem; color: var(--muted); font-size: .75rem; background: var(--panel); }
.footer-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 1.5rem; max-width: 78rem; margin: 0 auto; }
.footer-group { display: grid; align-content: start; gap: .45rem; min-width: 0; }
.footer-group h2 { border: 0; padding: 0; margin: 0 0 .45rem; color: var(--ink); font-size: .72rem; line-height: 1.3; letter-spacing: .06em; }
.footer-group a { color: var(--muted); text-underline-offset: .18em; }
.footer-group a:hover { color: var(--accent); }
.footer-note { max-width: 78rem; margin: 2rem auto 0; padding-top: 1rem; border-top: 1px solid var(--line); }
@media (max-width: 60rem) { .site-layout { display: block; } .site-rail { display: none; border-right: 0; border-bottom: 1px solid var(--line); padding: 1rem; } .site-rail.open { display: block; } .nav-toggle { display: block; } .page { width: min(58rem, calc(100% - 2rem)); padding-top: 3rem; } }
@media (max-width: 48rem) { .home-feature { grid-template-columns: 1fr; gap: 2rem; margin-bottom: 3.5rem; } .home-feature h1 { max-width: 12ch; } .state-grid { margin-top: 1.5rem; } .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media print { .site-header, .site-footer { position: static; } .site-header nav, .nav-toggle, .theme-toggle { display: none; } .page { width: 100%; padding: 0; } a { color: inherit; } }