:root {
  color-scheme: light dark;

  /* Warm editorial palette, HSL so dark mode is a clean recompute. */
  --bg: hsl(30, 20%, 99%);
  --bg-subtle: hsl(30, 15%, 96%);
  --bg-muted: hsl(30, 12%, 93%);
  --fg: hsl(20, 10%, 15%);
  --fg-secondary: hsl(20, 5%, 38%);
  --fg-muted: hsl(20, 5%, 52%);
  --fg-faint: hsl(20, 5%, 68%);
  --border: hsl(30, 15%, 86%);
  --border-light: hsl(30, 15%, 92%);
  --accent: hsl(25, 70%, 42%);
  --accent-light: hsl(25, 60%, 94%);

  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, "Helvetica Neue", Arial, sans-serif;
  --display: "Charter", "Iowan Old Style", "Source Serif Pro", "Cambria", Georgia, serif;
  --mono: ui-monospace, SFMono-Regular, "JetBrains Mono", "Menlo", "Roboto Mono", monospace;

  --shadow-sm: 0 1px 2px hsl(30 20% 20% / 0.04);
  --shadow: 0 2px 4px hsl(30 20% 20% / 0.05), 0 4px 12px hsl(30 20% 20% / 0.04);

  --ok: hsl(150, 55%, 38%);
  --ok-soft: hsl(145, 50%, 92%);
  --err: hsl(2, 70%, 50%);
  --err-soft: hsl(2, 72%, 94%);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: hsl(20, 8%, 10%);
    --bg-subtle: hsl(20, 6%, 13%);
    --bg-muted: hsl(20, 6%, 17%);
    --fg: hsl(30, 18%, 92%);
    --fg-secondary: hsl(20, 8%, 70%);
    --fg-muted: hsl(20, 8%, 56%);
    --fg-faint: hsl(20, 8%, 42%);
    --border: hsl(20, 6%, 24%);
    --border-light: hsl(20, 6%, 19%);
    --accent: hsl(25, 80%, 64%);
    --accent-light: hsl(25, 40%, 20%);
    --shadow-sm: 0 1px 2px hsl(0 0% 0% / 0.30);
    --shadow: 0 2px 4px hsl(0 0% 0% / 0.30), 0 4px 12px hsl(0 0% 0% / 0.25);
    --ok: hsl(150, 55%, 55%);
    --ok-soft: hsl(150, 30%, 18%);
    --err: hsl(2, 75%, 64%);
    --err-soft: hsl(2, 40%, 20%);
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--fg);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

::selection { background: var(--accent-light); color: var(--fg); }

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 1.5rem;
  width: 100%;
}
.container-wide { max-width: 1280px; }

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: hsl(from var(--accent) h s l / 0.35);
  text-underline-offset: 2px;
  transition: text-decoration-color 0.12s ease;
}
a:hover { text-decoration-color: var(--accent); }

/* ---- Site header ---- */
.site-header {
  border-bottom: 1px solid var(--border-light);
  background: var(--bg);
  padding: 1rem 0;
  font-size: 0.875rem;
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: saturate(180%) blur(8px);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.site-header .brand {
  font-family: var(--mono);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.01em;
  color: var(--fg);
  text-decoration: none;
  display: inline-flex;
  align-items: baseline;
  gap: 0.4rem;
}
.site-header .brand:hover { color: var(--accent); }
.site-header .brand .tld { color: var(--accent); }
.site-header nav { display: flex; flex-wrap: wrap; gap: 0.25rem 1.3rem; }
.site-header nav a {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--fg-muted);
  text-decoration: none;
  letter-spacing: 0.02em;
}
.site-header nav a:hover { color: var(--accent); }
.site-header nav a.active { color: var(--accent); font-weight: 600; }

main.container, main.site-main { flex: 1; }
main.site-main { width: 100%; }

/* ---- Site footer ---- */
.site-footer {
  border-top: 1px solid var(--border-light);
  background: var(--bg-subtle);
  padding: 1.75rem 0;
  color: var(--fg-muted);
  font-size: 0.825rem;
  margin-top: 4rem;
}
.site-footer p { margin: 0; }
.site-footer a { color: var(--fg-secondary); }
.site-footer a:hover { color: var(--accent); }

/* ============================================================
   Landing page
   ============================================================ */
.hero { padding: 4rem 0 2.5rem; max-width: 52rem; }
.hero-kicker {
  font-family: var(--mono); font-size: 0.78rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent); margin: 0 0 0.85rem;
}
.hero h1 {
  font-family: var(--display); font-size: 4.25rem; font-weight: 600;
  letter-spacing: -0.03em; line-height: 0.98; margin: 0; color: var(--fg);
}
@media (max-width: 600px) { .hero h1 { font-size: 2.8rem; } }
.hero-tag {
  font-family: var(--display); font-size: 1.5rem; color: var(--fg-secondary);
  margin: 0.7rem 0 1.25rem; font-style: italic;
}
.hero-lede { font-size: 1.1rem; line-height: 1.7; color: var(--fg-secondary); margin: 0 0 1.75rem; }
.hero-lede b { color: var(--fg); font-weight: 600; }
.hero-lede code, .band-note code, .explainer code {
  font-family: var(--mono); font-size: 0.85em; background: var(--bg-muted);
  padding: 0.08em 0.35em; border-radius: 4px;
}
.hero-cta { display: flex; flex-wrap: wrap; gap: 0.75rem; margin: 0 0 1.5rem; }
.btn-primary, .btn-ghost {
  display: inline-block; font-family: var(--mono); font-size: 0.85rem; font-weight: 600;
  padding: 0.65rem 1.15rem; border-radius: 9px; text-decoration: none; transition: all 0.12s ease;
}
.btn-primary { background: var(--accent); color: #fff; border: 1px solid transparent; }
.btn-primary:hover { filter: brightness(1.07); }
.btn-ghost { background: var(--bg-subtle); color: var(--fg); border: 1px solid var(--border); }
.btn-ghost:hover { border-color: var(--fg-faint); }
.hero-status {
  font-family: var(--mono); font-size: 0.8rem; color: var(--fg-muted);
  border-left: 3px solid var(--accent); padding-left: 0.8rem; margin: 0;
}

.band, .explainer, .explore { padding: 2.75rem 0; border-top: 1px solid var(--border-light); }
.band h2, .explainer h2, .explore h2 {
  font-family: var(--display); font-size: 1.8rem; font-weight: 600;
  letter-spacing: -0.015em; margin: 0 0 1.25rem; color: var(--fg);
}
.explainer p { font-size: 1.05rem; line-height: 1.75; color: var(--fg-secondary); max-width: 52rem; margin: 0 0 1rem; }
.explainer p b { color: var(--fg); }
.explainer-hint { font-family: var(--mono); font-size: 0.85rem; color: var(--accent); }
.explainer-hint em { font-style: normal; font-weight: 600; }
.band-note { font-size: 1.02rem; line-height: 1.7; color: var(--fg-secondary); max-width: 52rem; margin: 1rem 0 0; }

/* one-breath flow strip */
.flow-strip { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem; margin: 1.25rem 0 0; }
.flow-step {
  font-family: var(--mono); font-size: 0.82rem; color: var(--fg);
  background: var(--bg-subtle); border: 1px solid var(--border);
  border-radius: 8px; padding: 0.45rem 0.75rem; white-space: nowrap;
}
.flow-step b { color: var(--accent); margin-right: 0.3rem; }
.flow-step.muted { color: var(--fg-muted); border-style: dashed; }
.flow-strip i { color: var(--fg-faint); font-style: normal; }

/* feature grid */
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1rem; }
.feature {
  background: var(--bg); border: 1px solid var(--border); border-radius: 12px;
  padding: 1.25rem 1.3rem; box-shadow: var(--shadow-sm);
}
.feature h3 { font-family: var(--sans); font-size: 1.05rem; font-weight: 600; margin: 0 0 0.5rem; color: var(--fg); }
.feature p { font-size: 0.92rem; line-height: 1.6; color: var(--fg-secondary); margin: 0 0 0.75rem; }
.feature em { font-style: italic; color: var(--fg); }
.feature a { font-family: var(--mono); font-size: 0.75rem; color: var(--accent); text-decoration: none; }
.feature a:hover { text-decoration: underline; }
.feature code { font-family: var(--mono); font-size: 0.82em; background: var(--bg-muted); padding: 0.06em 0.3em; border-radius: 4px; }

/* explore cards */
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 0.9rem; }
.card {
  display: flex; flex-direction: column; gap: 0.3rem; text-decoration: none;
  background: var(--bg-subtle); border: 1px solid var(--border-light); border-radius: 10px;
  padding: 1.05rem 1.15rem; transition: border-color 0.12s ease, transform 0.05s ease;
}
.card:hover { border-color: var(--accent); transform: translateY(-1px); }
.card-t { font-weight: 600; color: var(--fg); }
.card-d { font-size: 0.88rem; color: var(--fg-secondary); }

/* embedded interactive diagrams (iframes) */
iframe.embed {
  width: 100%;
  height: 560px;
  border: 1px solid var(--border-light);
  border-radius: 12px;
  background: var(--bg);
  margin: 1.5rem 0 0;
  box-shadow: var(--shadow-sm);
}
iframe.embed.tall { height: 720px; }

/* ============================================================
   Docs: three-column shell (sidebar | content | TOC)
   ============================================================ */
.doc-shell {
  max-width: 1280px;
  margin: 0 auto;
  width: 100%;
  padding: 0 1.5rem;
}
@media (min-width: 1000px) {
  .doc-shell {
    display: grid;
    grid-template-columns: 220px minmax(0, 1fr) 200px;
    gap: 2.75rem;
    align-items: start;
  }
}

/* left sidebar */
.doc-side {
  padding: 2rem 0 1rem;
  font-size: 0.9rem;
}
@media (min-width: 1000px) {
  .doc-side {
    position: sticky;
    top: 4rem;
    max-height: calc(100vh - 5rem);
    overflow-y: auto;
    border-right: 1px solid var(--border-light);
    padding-right: 1rem;
  }
}
.doc-side-label {
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--fg-faint);
  margin: 1.4rem 0 0.5rem;
}
.doc-side-label:first-child { margin-top: 0; }
.doc-side-list { list-style: none; margin: 0 0 0.25rem; padding: 0; }
.doc-side-list li { margin: 0.05rem 0; }
.doc-side-list a {
  display: block;
  color: var(--fg-secondary);
  text-decoration: none;
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
  line-height: 1.35;
}
.doc-side-list a:hover { color: var(--fg); background: var(--bg-subtle); }
.doc-side-list a.active { color: var(--accent); font-weight: 600; background: var(--accent-light); }

/* mobile sidebar disclosure */
.doc-side-toggle {
  display: block;
  width: 100%;
}
@media (min-width: 1000px) { .doc-side-toggle { display: none; } }
.doc-side-toggle summary {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--fg-muted);
  cursor: pointer;
  padding: 0.9rem 0;
  list-style: none;
}
.doc-side-toggle summary::-webkit-details-marker { display: none; }
.doc-side-toggle summary::before { content: "☰ "; }

/* main column */
.doc-main { min-width: 0; padding: 2.25rem 0 2rem; }

.doc-body { font-size: 1rem; line-height: 1.7; color: var(--fg-secondary); }
.doc-body > *:first-child { margin-top: 0; }

.doc-body h1 {
  font-family: var(--display);
  font-size: 2.5rem;
  font-weight: 600;
  letter-spacing: -0.022em;
  line-height: 1.12;
  margin: 0 0 1.5rem;
  color: var(--fg);
}
.doc-body h2 {
  font-family: var(--sans);
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.012em;
  color: var(--fg);
  margin: 3rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-light);
  scroll-margin-top: 5rem;
}
.doc-body h3 {
  font-family: var(--sans);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--fg);
  margin: 2rem 0 0.5rem;
  scroll-margin-top: 5rem;
}
.doc-body h4 {
  font-family: var(--sans);
  font-size: 1rem;
  font-weight: 600;
  color: var(--fg);
  margin: 1.5rem 0 0.5rem;
  scroll-margin-top: 5rem;
}
.doc-body .heading-link { color: inherit; text-decoration: none; }
.doc-body .heading-link:hover { color: var(--accent); }

.doc-body p { margin: 0.85rem 0; }
.doc-body ul, .doc-body ol { padding-left: 1.5rem; margin: 0.85rem 0; }
.doc-body li { margin: 0.3rem 0; }
.doc-body li > p:first-child { margin-top: 0; }
.doc-body li > p:last-child { margin-bottom: 0; }
.doc-body strong { font-weight: 600; color: var(--fg); }
.doc-body em { font-style: italic; }

.doc-body blockquote {
  border-left: 3px solid var(--accent);
  margin: 1.25rem 0;
  padding: 0.4rem 1.1rem;
  background: var(--bg-subtle);
  border-radius: 0 8px 8px 0;
  color: var(--fg-muted);
}
.doc-body blockquote p { margin: 0.35rem 0; }

.doc-body code {
  font-family: var(--mono);
  font-size: 0.875em;
  background: var(--bg-muted);
  padding: 0.1em 0.4em;
  border-radius: 4px;
  color: var(--fg);
}
.doc-body pre {
  background: var(--bg-subtle);
  border: 1px solid var(--border-light);
  padding: 1rem 1.1rem;
  border-radius: 8px;
  overflow-x: auto;
  font-size: 0.88rem;
  line-height: 1.55;
  margin: 1.1rem 0;
}
.doc-body pre code { background: none; padding: 0; font-size: inherit; }

.doc-body table {
  border-collapse: collapse;
  margin: 1.25rem 0;
  font-size: 0.92rem;
  width: 100%;
  display: block;
  overflow-x: auto;
}
.doc-body th {
  text-align: left;
  padding: 0.55rem 0.9rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--fg-muted);
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border-light);
  white-space: nowrap;
}
.doc-body td { padding: 0.6rem 0.9rem; border-bottom: 1px solid var(--border-light); vertical-align: top; }
.doc-body tr:last-child td { border-bottom: 0; }
.doc-body hr { border: 0; border-top: 1px solid var(--border-light); margin: 2.5rem 0; }

.doc-footer {
  margin-top: 3.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border-light);
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--fg-muted);
}
.doc-footer a { color: var(--fg-secondary); text-decoration: none; }
.doc-footer a:hover { color: var(--accent); }
.doc-footer code { font-size: inherit; background: none; padding: 0; }

/* right TOC */
.doc-toc { display: none; }
@media (min-width: 1000px) {
  .doc-toc {
    display: block;
    position: sticky;
    top: 4rem;
    align-self: start;
    font-size: 0.85rem;
    max-height: calc(100vh - 5rem);
    overflow-y: auto;
    padding: 2.25rem 0 1rem;
  }
}
.doc-toc-label {
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--fg-faint);
  margin: 0 0 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-light);
}
.doc-toc ul { list-style: none; margin: 0; padding: 0; }
.doc-toc li { margin: 0.4rem 0; line-height: 1.4; }
.doc-toc li.level-3 { padding-left: 1rem; font-size: 0.8rem; }
.doc-toc a { color: var(--fg-secondary); text-decoration: none; display: block; padding: 0.05rem 0; }
.doc-toc a:hover { color: var(--accent); }
.doc-toc-empty { display: none; }

/* ============================================================
   Signature-flow diagram (sender -> receiver), used in docs via raw HTML.
   Selectors are prefixed with .sigflow so the .doc-body list/typography
   rules don't override them.
   ============================================================ */
.sigflow {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.9rem;
  margin: 1.75rem 0;
}
@media (min-width: 720px) {
  .sigflow { grid-template-columns: 1fr auto 1fr; gap: 0; align-items: stretch; }
}
.sigflow .sigflow-col {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}
.sigflow .sigflow-sender { border-top: 3px solid var(--accent); }
.sigflow .sigflow-receiver { border-top: 3px solid var(--ok); }
.sigflow .sigflow-head {
  display: flex; align-items: baseline; justify-content: space-between; gap: 0.75rem;
  padding: 0.7rem 1rem; border-bottom: 1px solid var(--border-light); background: var(--bg-subtle);
}
.sigflow .sigflow-role {
  font-family: var(--mono); font-weight: 600; font-size: 0.78rem;
  letter-spacing: 0.05em; text-transform: uppercase;
}
.sigflow .sigflow-sender .sigflow-role { color: var(--accent); }
.sigflow .sigflow-receiver .sigflow-role { color: var(--ok); }
.sigflow .sigflow-key { font-family: var(--mono); font-size: 0.72rem; color: var(--fg-muted); white-space: nowrap; }
.sigflow .sigflow-steps {
  list-style: none; margin: 0; padding: 0.6rem;
  display: flex; flex-direction: column; gap: 0.5rem;
}
.sigflow .sigflow-steps li {
  display: flex; gap: 0.7rem; align-items: flex-start; margin: 0;
  padding: 0.6rem 0.65rem; border-radius: 8px; background: var(--bg-subtle);
}
.sigflow .sigflow-steps .n {
  flex: none; width: 1.65rem; height: 1.65rem; border-radius: 50%;
  display: grid; place-items: center; color: #fff;
  font-family: var(--mono); font-weight: 700; font-size: 0.8rem;
}
.sigflow .sigflow-sender .n { background: var(--accent); }
.sigflow .sigflow-receiver .n { background: var(--ok); }
.sigflow .sigflow-steps b { display: block; color: var(--fg); font-weight: 600; font-size: 0.92rem; line-height: 1.3; }
.sigflow .sigflow-steps p { margin: 0.15rem 0 0; font-size: 0.82rem; line-height: 1.45; color: var(--fg-muted); }
.sigflow .sigflow-steps code { font-size: 0.82em; }
.sigflow .sigflow-wire {
  position: relative;
  display: flex; align-items: center; justify-content: center;
  padding: 0.4rem 0.9rem;
}
.sigflow .sigflow-wire::before {
  content: ""; position: absolute; left: 50%; top: 0; bottom: 0; width: 2px;
  background: linear-gradient(180deg, var(--accent), var(--ok)); transform: translateX(-50%);
}
@media (min-width: 720px) {
  .sigflow .sigflow-wire { padding: 0 0.9rem; min-width: 6rem; }
  .sigflow .sigflow-wire::before {
    left: 0; right: 0; top: 50%; bottom: auto; width: auto; height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--ok)); transform: translateY(-50%);
  }
}
.sigflow .sigflow-wire .chip {
  position: relative; z-index: 1;
  font-family: var(--mono); font-size: 0.72rem; color: var(--fg-secondary);
  background: var(--bg-muted); border: 1px solid var(--border);
  border-radius: 999px; padding: 0.3rem 0.7rem; white-space: nowrap;
}
.sigflow .sigflow-wire .chip::after { content: " ↓"; }
@media (min-width: 720px) { .sigflow .sigflow-wire .chip::after { content: " →"; } }

/* ============================================================
   Interactive ladder / sequence diagram (Client -> Proxy -> Upstream),
   used in docs via raw HTML + a small inline script. .ladder-scoped.
   ============================================================ */
.ladder {
  border: 1px solid var(--border); border-radius: 12px; background: var(--bg);
  box-shadow: var(--shadow-sm); margin: 1.75rem 0; overflow: hidden;
}
.ladder .ladder-head {
  display: grid; grid-template-columns: repeat(3, 1fr);
  padding: 0.8rem 0.5rem; border-bottom: 1px solid var(--border-light); background: var(--bg-subtle);
}
.ladder .ladder-actor {
  justify-self: center; font-family: var(--mono); font-weight: 600; font-size: 0.78rem;
  letter-spacing: 0.03em; padding: 0.25rem 0.75rem; border-radius: 999px;
  border: 1px solid var(--border); color: var(--fg-muted); background: var(--bg);
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.ladder .a-client.on { color: #fff; background: var(--select); border-color: transparent; }
.ladder .a-proxy.on { color: #fff; background: var(--accent); border-color: transparent; }
.ladder .a-upstream.on { color: #fff; background: var(--ok); border-color: transparent; }

.ladder .ladder-body { position: relative; padding: 1rem 0.5rem; }
.ladder .ladder-life {
  position: absolute; top: 0.5rem; bottom: 0.5rem; width: 2px;
  background: repeating-linear-gradient(var(--border) 0 6px, transparent 6px 12px);
}
.ladder .ladder-life.l1 { left: 16.667%; } .ladder .ladder-life.l2 { left: 50%; } .ladder .ladder-life.l3 { left: 83.333%; }

.ladder .ladder-steps { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 0.55rem; position: relative; z-index: 1; }
.ladder .ladder-step { display: grid; grid-template-columns: repeat(3, 1fr); align-items: center; opacity: 0.3; transition: opacity 0.25s ease; }
.ladder .ladder-step.show { opacity: 1; }

/* notes attached to a lane */
.ladder .ladder-note {
  margin: 0 0.4rem; background: var(--bg); border: 1px solid var(--border); border-radius: 9px;
  padding: 0.5rem 0.7rem; font-size: 0.85rem; line-height: 1.4; box-shadow: var(--shadow-sm); color: var(--fg-secondary);
}
.ladder .ladder-note b { font-family: var(--mono); color: var(--fg); margin-right: 0.25rem; }
.ladder .ladder-note code { font-size: 0.82em; }
.ladder .lane-client .ladder-note { grid-column: 1; border-left: 3px solid var(--select); }
.ladder .lane-proxy .ladder-note { grid-column: 2; border-left: 3px solid var(--accent); }
.ladder .lane-upstream .ladder-note { grid-column: 3; border-left: 3px solid var(--ok); }
.ladder .ladder-step.active .ladder-note { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-light); }
.ladder .ladder-who {
  display: inline-block; font-style: normal; font-family: var(--mono); font-size: 0.6rem;
  text-transform: uppercase; letter-spacing: 0.05em; color: var(--fg-muted);
  border: 1px solid var(--border-light); border-radius: 4px; padding: 0 0.3rem; margin-bottom: 0.3rem;
}

/* messages: a centered chip above a banded connector that runs lifeline -> lifeline */
.ladder .ladder-step.msg { grid-template-columns: 1fr; justify-items: center; gap: 0.3rem; }
.ladder .ladder-chip {
  font-family: var(--mono); font-size: 0.76rem; color: var(--fg); text-align: center;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 0.35rem 0.65rem; box-shadow: var(--shadow-sm);
}
.ladder .ladder-chip code { font-size: 0.92em; background: var(--bg-muted); padding: 0.05em 0.3em; border-radius: 4px; }
.ladder .ladder-wire { display: block; align-self: stretch; height: 2px; position: relative; }
.ladder .ladder-step.c2p .ladder-wire { margin-left: 16.667%; margin-right: 50%; background: linear-gradient(90deg, var(--select), var(--accent)); }
.ladder .ladder-step.p2u .ladder-wire { margin-left: 50%; margin-right: 16.667%; background: linear-gradient(90deg, var(--accent), var(--ok)); }
.ladder .ladder-wire::after { content: "▸"; position: absolute; right: -6px; top: 50%; transform: translateY(-50%); font-size: 0.8rem; line-height: 0; }
.ladder .ladder-step.c2p .ladder-wire::after { color: var(--accent); }
.ladder .ladder-step.p2u .ladder-wire::after { color: var(--ok); }

/* footer controls + live "signatures on message" state */
.ladder .ladder-foot {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 0.75rem;
  padding: 0.7rem 0.9rem; border-top: 1px solid var(--border-light); background: var(--bg-subtle);
}
.ladder .ladder-controls { display: flex; align-items: center; gap: 0.4rem; flex-wrap: wrap; }
.ladder .lbtn {
  font-family: var(--mono); font-size: 0.76rem; font-weight: 600; color: var(--fg);
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 0.4rem 0.7rem; cursor: pointer;
}
.ladder .lbtn:hover { border-color: var(--fg-faint); }
.ladder .lbtn.primary { background: var(--accent); color: #fff; border-color: transparent; }
.ladder .ladder-count { font-family: var(--mono); font-size: 0.76rem; color: var(--fg-muted); margin-left: 0.3rem; }
.ladder .ladder-count b { color: var(--fg); }
.ladder .ladder-state { font-family: var(--mono); font-size: 0.74rem; color: var(--fg-muted); display: flex; align-items: center; gap: 0.4rem; }
.ladder .ladder-sigs { display: inline-flex; gap: 0.3rem; }
.ladder .ladder-sigs .sig { color: #fff; border-radius: 5px; padding: 0.05rem 0.42rem; font-weight: 600; }
.ladder .ladder-sigs .sc { background: var(--select); }
.ladder .ladder-sigs .sp { background: var(--accent); }

@media (max-width: 640px) {
  .ladder .ladder-life { display: none; }
  .ladder .ladder-step { grid-template-columns: 1fr; }
  .ladder .lane-client .ladder-note, .ladder .lane-proxy .ladder-note, .ladder .lane-upstream .ladder-note { grid-column: 1; }
  .ladder .ladder-step.c2p .ladder-wire, .ladder .ladder-step.p2u .ladder-wire { margin-left: 1rem; margin-right: 1rem; }
}

/* ============================================================
   Multi-language code tabs (transformed from MDX <Tabs>/<TabItem>).
   ============================================================ */
.httabs { margin: 1.25rem 0; }
.httabs-nav {
  display: flex; flex-wrap: wrap; gap: 0.2rem;
  border-bottom: 1px solid var(--border-light); margin-bottom: 0;
}
.httabs .httab {
  font-family: var(--mono); font-size: 0.8rem; font-weight: 600; color: var(--fg-muted);
  background: none; border: 0; border-bottom: 2px solid transparent;
  padding: 0.45rem 0.8rem; cursor: pointer; margin-bottom: -1px;
}
.httabs .httab:hover { color: var(--fg); }
.httabs .httab.active { color: var(--accent); border-bottom-color: var(--accent); }
.httabs-panel { display: none; }
.httabs-panel.active { display: block; }
.httabs-panel > pre:first-child { margin-top: 0.9rem; }

/* tag pills (reused on cards) */
.tag {
  display: inline-block;
  padding: 0.12rem 0.5rem;
  border-radius: 4px;
  background: var(--bg-muted);
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--fg-muted);
  margin-right: 0.3rem;
  vertical-align: middle;
}