:root {
  color-scheme: dark;
  --bg: #080b0d;
  --surface: #0d1215;
  --surface-2: #12191d;
  --surface-3: #182126;
  --ink: #ecf2f3;
  --muted: #9babad;
  --line: #263438;
  --cyan: #55d6d1;
  --amber: #f0b44d;
  --red: #ef796f;
  --green: #7bd88f;
  --blue: #72a7ff;
  --sidebar: 19rem;
  --reading: 78ch;
  --radius: 5px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 5rem; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "IBM Plex Sans", "Segoe UI", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: .22;
  background-image:
    linear-gradient(rgba(85,214,209,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(85,214,209,.035) 1px, transparent 1px);
  background-size: 24px 24px;
  mask-image: linear-gradient(to bottom, black, transparent 85%);
  z-index: -1;
}
a { color: var(--cyan); text-underline-offset: .2em; }
a:hover { color: #9ce9e6; }
button, input { font: inherit; }
button { cursor: pointer; }
.skip-link { position: fixed; left: 1rem; top: -5rem; background: var(--amber); color: #111; padding: .75rem 1rem; z-index: 100; }
.skip-link:focus { top: 1rem; }
#progress { position: fixed; inset: 0 auto auto 0; height: 3px; width: 0; background: var(--amber); z-index: 90; }
.topbar {
  display: none;
  position: sticky;
  top: 0;
  z-index: 50;
  align-items: center;
  gap: .75rem;
  padding: .65rem 1rem;
  background: rgba(8,11,13,.96);
  border-bottom: 1px solid var(--line);
}
.menu-button { background: var(--surface-2); border: 1px solid var(--line); color: var(--ink); min-width: 44px; min-height: 44px; border-radius: var(--radius); }
.wordmark { font: 700 .82rem/1.1 "DejaVu Sans Mono", monospace; letter-spacing: .12em; }
.layout { display: grid; grid-template-columns: var(--sidebar) minmax(0, 1fr); min-height: 100vh; }
.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  padding: 1.4rem 1rem 2rem;
  background: rgba(10,14,16,.98);
  border-right: 1px solid var(--line);
  scrollbar-width: thin;
}
.brand { display: grid; grid-template-columns: 2.5rem 1fr; gap: .8rem; align-items: center; margin-bottom: 1.3rem; }
.brand-mark { display: grid; place-items: center; width: 2.5rem; height: 2.5rem; border: 1px solid var(--cyan); color: var(--cyan); font: 700 .8rem/1 monospace; }
.brand strong { display: block; font-size: .93rem; letter-spacing: .06em; }
.brand small { display: block; color: var(--muted); font-size: .72rem; }
.search-wrap { position: relative; margin-bottom: 1.15rem; }
.search-wrap label { display: block; color: var(--muted); font: 600 .66rem/1.2 monospace; text-transform: uppercase; letter-spacing: .13em; margin-bottom: .4rem; }
#search { width: 100%; min-height: 44px; padding: .65rem .75rem; background: var(--surface); color: var(--ink); border: 1px solid var(--line); border-radius: var(--radius); outline: none; }
#search:focus { border-color: var(--cyan); box-shadow: 0 0 0 2px rgba(85,214,209,.15); }
.search-count { color: var(--muted); font-size: .7rem; margin-top: .35rem; min-height: 1em; }
.nav-label { color: var(--amber); font: 700 .66rem/1.2 monospace; letter-spacing: .14em; text-transform: uppercase; margin: 1.25rem .5rem .5rem; }
nav ol { list-style: none; padding: 0; margin: 0; }
nav a { display: grid; grid-template-columns: 1.7rem 1fr; gap: .2rem; padding: .4rem .5rem; color: var(--muted); text-decoration: none; font-size: .78rem; line-height: 1.3; border-radius: 3px; }
nav a span { color: #68787b; font-family: monospace; }
nav a:hover, nav a.active { color: var(--ink); background: var(--surface-2); }
nav a.active span { color: var(--cyan); }
.side-note { margin-top: 1.4rem; padding: .8rem; border: 1px solid var(--line); color: var(--muted); font-size: .73rem; }
.main { min-width: 0; }
.hero { padding: clamp(3rem, 7vw, 7rem) clamp(1.4rem, 6vw, 6rem) 4rem; border-bottom: 1px solid var(--line); }
.hero-inner { max-width: 1050px; }
.eyebrow, .section-kicker { color: var(--cyan); font: 700 .73rem/1.2 "DejaVu Sans Mono", monospace; letter-spacing: .15em; text-transform: uppercase; }
h1 { max-width: 14ch; margin: .65rem 0 1.25rem; font-size: clamp(3rem, 7vw, 7.4rem); line-height: .88; letter-spacing: -.055em; font-weight: 800; }
.hero .dek { max-width: 67ch; margin: 0; font-size: clamp(1.08rem, 1.7vw, 1.45rem); color: #c4d0d2; line-height: 1.5; }
.hero-meta { display: flex; flex-wrap: wrap; gap: .7rem 1.8rem; margin-top: 2rem; padding-top: 1.2rem; border-top: 1px solid var(--line); color: var(--muted); font: .76rem/1.4 monospace; }
.hero-meta b { color: var(--amber); font-weight: 600; }
.content { max-width: 1150px; padding: 0 clamp(1.4rem, 6vw, 6rem) 8rem; }
.chapter { display: grid; grid-template-columns: minmax(8rem, 13rem) minmax(0, var(--reading)); gap: clamp(1.5rem, 4vw, 4.5rem); padding: 4.5rem 0; border-bottom: 1px solid var(--line); }
.chapter.hidden { display: none; }
.chapter-index { position: sticky; top: 2rem; align-self: start; }
.chapter-index .num { color: var(--amber); font: 700 2.2rem/1 monospace; }
.chapter-index .tag { display: block; margin-top: .8rem; color: var(--muted); font: .68rem/1.4 monospace; text-transform: uppercase; letter-spacing: .12em; }
.chapter-body { min-width: 0; }
h2 { margin: 0 0 1.2rem; font-size: clamp(1.85rem, 3.2vw, 3.15rem); line-height: 1.05; letter-spacing: -.035em; }
h3 { margin: 2.4rem 0 .65rem; font-size: 1.13rem; line-height: 1.3; letter-spacing: -.01em; }
h4 { margin: 1.7rem 0 .4rem; font-size: .98rem; color: var(--amber); }
p { margin: .65rem 0 1rem; }
ul, ol { padding-left: 1.25rem; }
li { margin: .35rem 0; }
strong { color: #fff; }
.lead { font-size: 1.12rem; color: #cbd6d8; }
.callout { margin: 1.5rem 0; padding: 1rem 1.1rem; background: var(--surface-2); border: 1px solid var(--line); border-radius: var(--radius); }
.callout strong:first-child { color: var(--amber); }
.callout.danger strong:first-child { color: var(--red); }
.callout.safe strong:first-child { color: var(--green); }
.protocol-stack { display: grid; gap: .35rem; max-width: 34rem; margin: 1.5rem 0; }
.layer { display: grid; grid-template-columns: 6rem 1fr; gap: 1rem; align-items: center; padding: .7rem .9rem; border: 1px solid var(--line); background: var(--surface); }
.layer b { color: var(--cyan); font-family: monospace; }
.layer.apps { border-color: #62502c; background: #17150f; }
.diagram { overflow-x: auto; margin: 1.5rem 0; padding: 1.2rem; border: 1px solid var(--line); background: #070a0c; color: #b8c7c9; font: .78rem/1.55 "DejaVu Sans Mono", monospace; white-space: pre; }
.table-wrap { overflow-x: auto; margin: 1.4rem 0; }
table { width: 100%; border-collapse: collapse; font-size: .88rem; }
th, td { padding: .65rem .75rem; border: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--cyan); background: var(--surface-2); font: 700 .72rem/1.3 monospace; text-transform: uppercase; letter-spacing: .06em; }
code { padding: .1em .3em; background: var(--surface-3); color: #b5ece9; font-family: "DejaVu Sans Mono", monospace; font-size: .86em; }
.flow { counter-reset: flow; list-style: none; padding: 0; }
.flow li { counter-increment: flow; display: grid; grid-template-columns: 2rem 1fr; gap: .7rem; margin: .5rem 0; }
.flow li::before { content: counter(flow); display: grid; place-items: center; width: 1.8rem; height: 1.8rem; color: var(--amber); border: 1px solid #70582b; font: 700 .72rem monospace; }
.source-block { margin-top: 2rem; padding-top: 1rem; border-top: 1px dashed #344448; color: var(--muted); font-size: .78rem; }
.source-block strong { color: #bdc9cb; }
.source-block a { word-break: break-word; }
.glossary { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .7rem 1.5rem; }
.glossary div { padding: .7rem 0; border-bottom: 1px solid var(--line); }
.glossary dt { color: var(--cyan); font: 700 .82rem/1.2 monospace; }
.glossary dd { margin: .25rem 0 0; color: var(--muted); font-size: .86rem; }
footer { padding: 2.5rem clamp(1.4rem, 6vw, 6rem); color: var(--muted); border-top: 1px solid var(--line); font-size: .8rem; }
mark { color: #111; background: var(--amber); padding: .05em .1em; }
.no-results { display: none; margin: 4rem 0; color: var(--muted); }
.no-results.visible { display: block; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; }
@media (max-width: 900px) {
  .topbar { display: flex; }
  .layout { display: block; }
  .sidebar { position: fixed; inset: 0 auto 0 0; z-index: 60; width: min(88vw, 21rem); transform: translateX(-102%); transition: transform .2s ease; box-shadow: 10px 0 40px #000; }
  .sidebar.open { transform: translateX(0); }
  .chapter { grid-template-columns: 1fr; gap: 1rem; padding: 3.3rem 0; }
  .chapter-index { position: static; display: flex; gap: 1rem; align-items: baseline; }
  .chapter-index .tag { margin: 0; }
  h1 { font-size: clamp(3rem, 18vw, 6rem); }
}
@media (max-width: 580px) {
  .glossary { grid-template-columns: 1fr; }
  .hero { padding-top: 3rem; }
  .content { padding-bottom: 4rem; }
  .layer { grid-template-columns: 4.8rem 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}
@media print {
  :root { color-scheme: light; --bg: white; --surface: white; --surface-2: #f4f4f4; --surface-3: #eee; --ink: #111; --muted: #444; --line: #bbb; --cyan: #075b5b; --amber: #744700; }
  body { font-size: 11pt; }
  body::before, .sidebar, .topbar, #progress { display: none !important; }
  .layout { display: block; }
  .hero, .content, footer { padding-left: 0; padding-right: 0; }
  .chapter { display: block; page-break-inside: avoid; padding: 1.5rem 0; }
  .chapter-index { position: static; margin-bottom: .6rem; }
  a { color: #111; }
  a[href^="http"]::after { content: " (" attr(href) ")"; font-size: .75em; word-break: break-all; }
}