/* Layout: one narrow reading column; label/value rows for facts; nothing
   decorative. Built to read like a well-set résumé. */
:root {
  --paper: #f4f5f5;
  --surface: #ffffff;
  --ink: #15191c;
  --muted: #59636a;
  --rule: #d8dcde;
  --signal: #1f4f8f;          /* accent: navy */
  --grid-minor: #f1dcda;
  --grid-major: #e2b5b0;
  --code-bg: #eceeef;

  /* semantic, separate from the accent */
  --public: #8a5a00;
  --public-bg: #fbefd6;
  --mesh: #12695a;
  --mesh-bg: #dcf1ea;
  --friends: #35518f;
  --friends-bg: #e2e9f8;

  --font-display: "Archivo", "Helvetica Neue", Arial, sans-serif;
  --font-body: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;

  --step--1: 0.8125rem;
  --step-0: 1rem;
  --step-1: 1.1875rem;
  --step-2: 1.5rem;
  --step-3: 2.125rem;
  --step-4: clamp(2.25rem, 4vw + 1rem, 3.5rem);

  --measure: 68ch;
  --gutter: clamp(16px, 4vw, 40px);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0f1315;
    --surface: #161b1e;
    --ink: #e5e8ea;
    --muted: #96a1a8;
    --rule: #273034;
    --signal: #8fb4ec;
    --grid-minor: #1d1a1b;
    --grid-major: #3a2727;
    --code-bg: #1b2124;
    --public: #f0c060;
    --public-bg: #3a2c0c;
    --mesh: #6fd6b6;
    --mesh-bg: #0f3229;
    --friends: #9db7f2;
    --friends-bg: #1c2742;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #0f1315;
  --surface: #161b1e;
  --ink: #e5e8ea;
  --muted: #96a1a8;
  --rule: #273034;
  --signal: #8fb4ec;
  --grid-minor: #1d1a1b;
  --grid-major: #3a2727;
  --code-bg: #1b2124;
  --public: #f0c060;
  --public-bg: #3a2c0c;
  --mesh: #6fd6b6;
  --mesh-bg: #0f3229;
  --friends: #9db7f2;
  --friends-bg: #1c2742;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.6;
}

a { color: inherit; text-decoration-color: var(--signal); text-decoration-thickness: 1.5px; text-underline-offset: 3px; }
a:hover { color: var(--signal); }
:focus-visible { outline: 2px solid var(--signal); outline-offset: 3px; border-radius: 2px; }

h1, h2, h3 { font-family: var(--font-display); line-height: 1.1; text-wrap: balance; margin: 0; }
h1 { font-size: var(--step-4); font-weight: 700; font-stretch: 100%; letter-spacing: -0.02em; }
h2 { font-size: var(--step-3); font-weight: 700; letter-spacing: -0.01em; }
h3 { font-size: var(--step-1); font-weight: 700; font-stretch: 100%; }
p { margin: 0; }

.eyebrow, .label {
  font-family: var(--font-body);
  font-weight: 600;
  font-size: var(--step--1);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

code, pre, kbd { font-family: var(--font-mono); font-size: 0.9em; }
:not(pre) > code { background: var(--code-bg); padding: 0.1em 0.35em; border-radius: 3px; overflow-wrap: anywhere; }
pre {
  background: var(--code-bg);
  padding: 14px 16px;
  border-radius: 4px;
  overflow-x: auto;
  line-height: 1.5;
  margin: 0;
}

/* ── Frame ─────────────────────────────────────────────── */
.wrap { max-width: 1120px; margin: 0 auto; padding-inline: var(--gutter); }

.site-head {
  border-bottom: 1px solid var(--rule);
}
.site-head .wrap {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  flex-wrap: wrap; padding-block: 18px;
}
.wordmark {
  font-family: var(--font-display); font-weight: 700;
  font-size: 1.05rem; letter-spacing: -0.01em; text-decoration: none;
}
.wordmark span { color: var(--signal); }
.site-nav { display: flex; gap: 20px; flex-wrap: wrap; font-size: 0.95rem; }
.site-nav a { text-decoration: none; color: var(--muted); }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--ink); }
.site-nav a[aria-current="page"] { text-decoration: underline; text-decoration-color: var(--signal); }

.site-foot { border-top: 1px solid var(--rule); margin-top: 96px; }
.site-foot .wrap {
  display: flex; justify-content: space-between; gap: 12px 24px; flex-wrap: wrap;
  padding-block: 28px; color: var(--muted); font-size: var(--step--1);
}

/* ── Front page ────────────────────────────────────────── */
.intro { padding-block: clamp(48px, 9vw, 96px) 8px; display: grid; gap: 18px; max-width: 62ch; }
.intro h1 { margin-bottom: 4px; }
.intro .lede { font-size: var(--step-1); color: var(--ink); }
.intro p:not(.lede) { color: var(--muted); }

.facts { margin: 40px 0 0; max-width: 62ch; border-top: 1px solid var(--rule); }
.facts > div { display: grid; grid-template-columns: 9rem minmax(0, 1fr); gap: 16px; padding-block: 12px; border-bottom: 1px solid var(--rule); }
.facts dt { font-size: 0.9rem; font-weight: 600; color: var(--ink); }
.facts dd { margin: 0; color: var(--muted); }
@media (max-width: 520px) { .facts > div { grid-template-columns: 1fr; gap: 2px; } }

.next { margin-top: 40px; max-width: 62ch; display: grid; gap: 0; }
.next a {
  display: flex; justify-content: space-between; gap: 16px; padding-block: 14px;
  border-bottom: 1px solid var(--rule); text-decoration: none; font-weight: 500;
}
.next a:first-child { border-top: 1px solid var(--rule); }
.next a span:last-child { color: var(--signal); transition: transform .15s ease; }
.next a:hover span:last-child { transform: translateX(3px); }

/* ── Long-form pages ───────────────────────────────────── */
.page-head { padding-block: clamp(40px, 7vw, 80px) 32px; display: grid; gap: 16px; }
.page-head h1 { font-size: var(--step-4); }
.page-head .lede { font-size: var(--step-1); max-width: 52ch; color: var(--muted); }

.prose { display: grid; gap: 18px; max-width: var(--measure); min-width: 0; }
.prose ul, .prose ol { margin: 0; padding-left: 1.25em; display: grid; gap: 8px; }
.prose li::marker { color: var(--signal); }
.prose h2 { margin-top: 40px; }
.prose h3 { margin-top: 16px; }
.prose strong { font-weight: 600; }

.section { display: grid; grid-template-columns: 11rem minmax(0, 1fr); gap: 32px; padding-block: 40px; border-top: 1px solid var(--rule); }
.section > .label { padding-top: 10px; }
@media (max-width: 820px) {
  .section { grid-template-columns: 1fr; gap: 12px; padding-block: 32px; }
  .section > .label { padding-top: 0; }
}

/* Spec list: label / value rows */
.spec { display: grid; margin: 0; border-top: 1px solid var(--rule); }
.spec > div { display: grid; grid-template-columns: 10rem minmax(0, 1fr); gap: 16px; padding-block: 12px; border-bottom: 1px solid var(--rule); }
.spec dt { font-size: 0.9rem; font-weight: 600; color: var(--ink); }
.spec dd { color: var(--muted); }
.spec dd { margin: 0; }
@media (max-width: 520px) { .spec > div { grid-template-columns: 1fr; gap: 2px; } }

/* Tables */
.table-scroll { overflow-x: auto; border: 1px solid var(--rule); border-radius: 6px; background: var(--surface); }
table { border-collapse: collapse; width: 100%; font-size: 0.925rem; }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--rule); vertical-align: top; }
tr:last-child td { border-bottom: 0; }
th { font-family: var(--font-mono); font-size: var(--step--1); font-weight: 500; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); white-space: nowrap; }
td { font-variant-numeric: tabular-nums; }
td.nowrap { white-space: nowrap; }

.pill {
  display: inline-block; font-family: var(--font-mono); font-size: 0.75rem; font-weight: 500;
  padding: 2px 8px; border-radius: 999px; white-space: nowrap; letter-spacing: 0.02em;
}
.pill.public { color: var(--public); background: var(--public-bg); }
.pill.mesh { color: var(--mesh); background: var(--mesh-bg); }
.pill.friends { color: var(--friends); background: var(--friends-bg); }

.callout { border-left: 3px solid var(--signal); padding: 4px 0 4px 16px; color: var(--ink); }

/* Docs layout with contents rail */
.docs { display: grid; grid-template-columns: 13rem minmax(0, 1fr); gap: 48px; align-items: start; }
.toc { position: sticky; top: calc(env(safe-area-inset-top, 0px) + 24px); display: grid; gap: 10px; padding-top: 40px; }
.toc ol { list-style: none; margin: 0; padding: 0; display: grid; gap: 2px; counter-reset: toc; }
.toc a {
  display: grid; grid-template-columns: 2rem 1fr; text-decoration: none; color: var(--muted);
  font-size: 0.9rem; padding: 4px 0; border-left: 2px solid transparent; padding-left: 10px;
}
.toc a span { font-family: var(--font-mono); font-size: 0.75rem; padding-top: 3px; }
.toc a:hover { color: var(--ink); }
.toc a.active { color: var(--ink); border-left-color: var(--signal); }
.docs-body { min-width: 0; }
.docs-body .section { grid-template-columns: 1fr; gap: 20px; }
.docs-body .section > header { display: grid; gap: 6px; }
@media (max-width: 960px) {
  .docs { grid-template-columns: 1fr; gap: 0; }
  .toc { position: static; padding-top: 0; padding-bottom: 24px; }
  .toc ol { grid-template-columns: repeat(auto-fill, minmax(min(100%, 200px), 1fr)); }
}

/* Topology diagram */
.topo { display: grid; gap: 0; font-size: 0.925rem; }
.topo .node {
  border: 1px solid var(--rule); border-radius: 6px; background: var(--surface);
  padding: 16px 18px; display: grid; gap: 10px; min-width: 0;
}
.topo .node h3 { font-size: 1.05rem; display: flex; gap: 10px; align-items: baseline; flex-wrap: wrap; }
.topo .node h3 small { font-family: var(--font-mono); font-weight: 400; font-size: 0.75rem; color: var(--muted); }
.topo .chips { display: flex; flex-wrap: wrap; gap: 6px; }
.topo .chip { font-family: var(--font-mono); font-size: 0.78rem; padding: 3px 8px; border-radius: 4px; background: var(--code-bg); }
.topo .chip.public { color: var(--public); background: var(--public-bg); }
.topo .link {
  display: flex; align-items: center; gap: 12px; padding: 10px 0 10px 22px;
  font-family: var(--font-mono); font-size: var(--step--1); color: var(--muted);
  border-left: 2px dashed var(--grid-major); margin-left: 24px;
}
.topo .row { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
@media (max-width: 720px) { .topo .row { grid-template-columns: 1fr; } }
.topo .internet { font-family: var(--font-mono); font-size: var(--step--1); color: var(--muted); padding-left: 24px; }

/* Layered defence list (ordered outside → in) */
.layers { list-style: none; margin: 0; padding: 0; counter-reset: layer; display: grid; gap: 0; border-top: 1px solid var(--rule); }
.layers > li { counter-increment: layer; display: grid; grid-template-columns: 2.75rem minmax(0, 1fr); gap: 12px; padding-block: 16px; border-bottom: 1px solid var(--rule); }
.layers > li::before { content: counter(layer, decimal-leading-zero); font-family: var(--font-mono); font-size: var(--step--1); color: var(--signal); padding-top: 3px; }
.layers h3 { margin-bottom: 6px; }
.layers ul { margin: 0; padding-left: 1.1em; display: grid; gap: 6px; color: var(--ink); }
.layers ul li::marker { color: var(--muted); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; }
}