:root {
  --paper: #f4f7fb;
  --surface: #ffffff;
  --surface-alt: #edf3f9;
  --ink: #243447;
  --muted: #627286;
  --faint: #8a99aa;
  --line: #d7e0ea;
  --line-strong: #b9c8d8;
  --blue: #1769e0;
  --blue-deep: #0b4cae;
  --blue-soft: #e8f0ff;
  --green: #18734b;
  --green-soft: #e5f4ed;
  --amber: #b77600;
  --amber-soft: #fff3d5;
  --shadow: 0 12px 28px rgba(32, 58, 89, .08);
  --radius: 10px;
  --max: 1180px;
  --sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  overflow-x: hidden;
}
a { color: var(--blue-deep); text-underline-offset: 3px; }
a:hover { color: var(--blue); }
button, input { font: inherit; }
button { cursor: pointer; }
[hidden] { display: none !important; }

.skip-link {
  position: fixed;
  z-index: 20;
  left: 12px;
  top: -60px;
  padding: 9px 14px;
  background: var(--ink);
  color: #fff;
  border-radius: 0 0 6px 6px;
}
.skip-link:focus { top: 0; }

.site-header {
  background: rgba(244, 247, 251, .96);
  border-bottom: 1px solid var(--line);
}
.header-shell {
  width: min(var(--max), calc(100% - 40px));
  margin: 0 auto;
  min-height: 76px;
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
  padding: 14px 0;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 760;
  letter-spacing: -.02em;
  text-decoration: none;
  white-space: nowrap;
}
.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 7px;
  background: var(--blue);
  color: #fff;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: -.08em;
}
.primary-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 5px 14px;
  margin-left: auto;
}
.primary-nav a {
  color: var(--muted);
  font-size: 13px;
  font-weight: 650;
  text-decoration: none;
}
.primary-nav a:hover, .primary-nav a[aria-current="page"] { color: var(--blue-deep); }
.header-meta {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .04em;
  text-transform: uppercase;
}
.status-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0 3px var(--green-soft);
}

.page-shell { width: min(var(--max), calc(100% - 40px)); margin: 0 auto; }
main { padding-bottom: 84px; }
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 28px 0 14px;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .04em;
  text-transform: uppercase;
}
.breadcrumbs a { color: var(--muted); }
.breadcrumb-separator { color: var(--line-strong); }
.eyebrow {
  margin: 0 0 14px;
  color: var(--blue-deep);
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 750;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.eyebrow::before {
  content: "";
  display: inline-block;
  width: 16px;
  height: 1px;
  margin: 0 8px 3px 0;
  background: var(--blue);
}
h1, h2, h3 { line-height: 1.18; letter-spacing: -.035em; }
h1 { max-width: 850px; margin: 0; font-size: clamp(2.25rem, 5.4vw, 4.55rem); font-weight: 790; }
h2 { margin: 0 0 14px; font-size: clamp(1.55rem, 3vw, 2.45rem); font-weight: 760; }
h3 { margin: 0 0 8px; font-size: 1.1rem; font-weight: 750; }
p { margin: 0 0 16px; }
.lede { max-width: 760px; margin-top: 22px; color: #405166; font-size: clamp(1.08rem, 1.7vw, 1.26rem); line-height: 1.65; }
.small-copy { color: var(--muted); font-size: .93rem; }
.mono { font-family: var(--mono); font-size: .91em; }

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(260px, .6fr);
  gap: 58px;
  align-items: end;
  padding: 54px 0 48px;
  border-bottom: 1px solid var(--line);
}
.hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 120px;
  height: 3px;
  background: var(--blue);
}
.hero h1 { text-wrap: balance; }
.hero-panel {
  align-self: stretch;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 20px;
  border: 1px solid var(--line-strong);
  border-top: 4px solid var(--blue);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.panel-label {
  margin-bottom: 20px;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.readout {
  display: flex;
  align-items: baseline;
  gap: 8px;
  border-top: 1px solid var(--line);
  padding: 14px 0 0;
}
.readout strong { font-size: 1.1rem; }
.readout span { color: var(--muted); font-family: var(--mono); font-size: 11px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 9px 17px;
  border: 1px solid transparent;
  border-radius: 6px;
  font-size: .92rem;
  font-weight: 720;
  line-height: 1.2;
  text-decoration: none;
  transition: background-color .16s ease, border-color .16s ease, transform .16s ease;
}
.button:hover { text-decoration: none; transform: translateY(-1px); }
.button-primary { background: var(--blue); color: #fff; }
.button-primary:hover { background: var(--blue-deep); color: #fff; }
.button-secondary { border-color: var(--line-strong); background: var(--surface); color: var(--ink); }
.button-secondary:hover { border-color: var(--blue); color: var(--blue-deep); }

.signal-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  padding: 20px 0 14px;
}
.signal-card {
  display: block;
  padding: 16px 18px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  text-decoration: none;
}
.signal-card:hover { border-color: var(--blue); color: var(--ink); }
.signal-card .signal-head { display: flex; gap: 8px; align-items: center; margin-bottom: 5px; }
.signal-card strong { font-size: .95rem; }
.signal-card p { margin: 0; color: var(--muted); font-size: .86rem; line-height: 1.45; }
.signal-number { color: var(--blue); font-family: var(--mono); font-size: .73rem; font-weight: 700; }

.content-section { padding: 56px 0 0; }
.section-head { max-width: 740px; margin-bottom: 24px; }
.section-head p { color: var(--muted); }
.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(260px, .75fr);
  gap: 42px;
  align-items: start;
}
.prose { max-width: 760px; }
.prose p { color: #405166; }
.prose h3 { margin-top: 28px; }
.prose ul, .prose ol { margin: 0 0 20px; padding-left: 22px; color: #405166; }
.prose li { margin: 7px 0; }
.side-note {
  position: sticky;
  top: 18px;
  padding: 20px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--blue);
  background: var(--surface);
}
.side-note h3 { font-family: var(--mono); font-size: .82rem; letter-spacing: .04em; text-transform: uppercase; }
.side-note p, .side-note li { color: var(--muted); font-size: .9rem; }
.side-note ul { margin: 12px 0 0; padding-left: 18px; }

.rank-list { display: grid; gap: 14px; }
.rank-card {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  gap: 18px;
  padding: 22px 20px;
  border: 1px solid var(--line);
  border-left: 4px solid var(--line-strong);
  background: var(--surface);
  box-shadow: 0 4px 14px rgba(32, 58, 89, .035);
}
.rank-card:first-child { border-left-color: var(--blue); }
.rank-index { color: var(--blue); font-family: var(--mono); font-size: 1.55rem; font-weight: 700; }
.rank-card h3 { margin-bottom: 5px; }
.rank-card h3 a { color: var(--ink); text-decoration: none; }
.rank-card h3 a:hover { color: var(--blue-deep); text-decoration: underline; }
.rank-card p { margin: 0; color: var(--muted); font-size: .93rem; }
.rank-tag {
  align-self: start;
  white-space: nowrap;
  padding: 4px 7px;
  border: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .04em;
  text-transform: uppercase;
}
.rank-card:first-child .rank-tag { border-color: #a8c5ff; background: var(--blue-soft); color: var(--blue-deep); }

.fact-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.fact-card { padding: 18px; border: 1px solid var(--line); background: var(--surface); }
.fact-card strong { display: block; margin-bottom: 5px; font-size: 1.05rem; }
.fact-card span { color: var(--muted); font-size: .87rem; }

.process-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--line); background: var(--surface); }
.process-step { min-height: 185px; padding: 20px; border-right: 1px solid var(--line); }
.process-step:last-child { border-right: 0; }
.process-step .step-code { display: block; margin-bottom: 32px; color: var(--blue); font-family: var(--mono); font-size: .72rem; font-weight: 700; letter-spacing: .09em; }
.process-step h3 { font-size: 1rem; }
.process-step p { margin: 0; color: var(--muted); font-size: .88rem; line-height: 1.5; }

.table-scroll { overflow-x: auto; border: 1px solid var(--line); background: var(--surface); }
.comparison-table { width: 100%; min-width: 650px; border-collapse: collapse; text-align: left; }
.comparison-table th, .comparison-table td { padding: 13px 16px; border-bottom: 1px solid var(--line); vertical-align: top; }
.comparison-table tr:last-child td { border-bottom: 0; }
.comparison-table th { background: var(--surface-alt); color: var(--muted); font-family: var(--mono); font-size: .72rem; letter-spacing: .06em; text-transform: uppercase; }
.comparison-table td { color: #405166; font-size: .9rem; }
.comparison-table td:first-child { color: var(--ink); font-weight: 700; }

.callout {
  margin: 24px 0;
  padding: 18px 20px;
  border: 1px solid #a8c5ff;
  border-left: 4px solid var(--blue);
  background: var(--blue-soft);
}
.callout h3 { color: var(--blue-deep); }
.callout p { margin: 0; color: #315378; }
.callout-warning {
  border-color: #e7c16d;
  border-left-color: var(--amber);
  background: var(--amber-soft);
}
.callout-warning h3 { color: #805300; }
.callout-warning p { color: #684b15; }

.faq-list { display: grid; gap: 10px; }
details { border: 1px solid var(--line); background: var(--surface); }
summary { cursor: pointer; padding: 17px 20px; color: var(--ink); font-weight: 720; list-style-position: inside; }
summary::marker { color: var(--blue); }
details > div { padding: 0 20px 17px 43px; color: var(--muted); }
details p { margin: 0; }

.article-hero { padding-bottom: 42px; }
.article-hero h1 { max-width: 920px; }
.article-hero .lede { max-width: 820px; }
.article-meta { display: flex; flex-wrap: wrap; gap: 10px 18px; margin-top: 20px; color: var(--faint); font-family: var(--mono); font-size: 11px; }
.article-layout { display: grid; grid-template-columns: minmax(0, 1fr) 270px; gap: 48px; align-items: start; }
.article-layout > .prose { max-width: none; }
.article-outline { position: sticky; top: 18px; padding: 16px; border: 1px solid var(--line); background: var(--surface); }
.article-outline strong { display: block; margin-bottom: 10px; color: var(--faint); font-family: var(--mono); font-size: 10px; letter-spacing: .1em; text-transform: uppercase; }
.article-outline a { display: block; padding: 6px 0; color: var(--muted); font-size: .88rem; text-decoration: none; }
.article-outline a:hover { color: var(--blue-deep); }

/* Diagnostic console */
.diagnostic-shell {
  padding: 28px;
  border: 1px solid var(--line-strong);
  border-top: 4px solid var(--blue);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.diagnostic-intro { max-width: 760px; margin-bottom: 28px; }
.diagnostic-intro p { color: var(--muted); }
.question-list { display: grid; gap: 12px; counter-reset: question; }
.question-card {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 14px;
  padding: 18px;
  border: 1px solid var(--line);
  background: #fbfdff;
}
.question-card::before {
  counter-increment: question;
  content: counter(question, decimal-leading-zero);
  color: var(--blue);
  font-family: var(--mono);
  font-size: .78rem;
  font-weight: 700;
}
.question-card fieldset { min-width: 0; margin: 0; padding: 0; border: 0; }
.question-card legend { width: 100%; margin-bottom: 12px; font-weight: 700; line-height: 1.4; }
.choice-row { display: flex; flex-wrap: wrap; gap: 8px; }
.choice { position: relative; }
.choice input { position: absolute; opacity: 0; pointer-events: none; }
.choice label {
  display: inline-flex;
  min-width: 78px;
  justify-content: center;
  padding: 6px 11px;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
  font-family: var(--mono);
  font-size: .76rem;
  font-weight: 700;
  text-transform: uppercase;
}
.choice input:checked + label { border-color: var(--blue); background: var(--blue-soft); color: var(--blue-deep); }
.choice input:focus-visible + label { outline: 3px solid rgba(23, 105, 224, .25); outline-offset: 2px; }
.diagnostic-controls { display: flex; align-items: center; flex-wrap: wrap; gap: 14px; margin-top: 22px; }
.diagnostic-controls .small-copy { margin: 0; }
.diagnostic-output { margin-top: 28px; padding: 24px; border: 1px solid var(--line-strong); background: var(--surface-alt); }
.output-header { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; padding-bottom: 16px; border-bottom: 1px solid var(--line); }
.output-header h2 { margin: 0; font-size: 1.45rem; }
.output-status { white-space: nowrap; padding: 5px 8px; border: 1px solid #a8c5ff; background: var(--blue-soft); color: var(--blue-deep); font-family: var(--mono); font-size: 10px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; }
.output-status.is-clear { border-color: #9dd1b6; background: var(--green-soft); color: var(--green); }
.output-status.is-warning { border-color: #e7c16d; background: var(--amber-soft); color: #805300; }
.diagnosis-list { display: grid; gap: 10px; margin: 18px 0 0; padding: 0; list-style: none; }
.diagnosis-item { display: grid; grid-template-columns: 10px minmax(0, 1fr); gap: 12px; padding: 14px; border: 1px solid var(--line); background: var(--surface); }
.diagnosis-item .severity-dot { width: 10px; height: 10px; margin-top: 6px; border-radius: 50%; background: var(--blue); }
.diagnosis-item.severity-critical .severity-dot, .diagnosis-item.severity-high .severity-dot { background: var(--amber); }
.diagnosis-item.severity-low .severity-dot { background: var(--green); }
.diagnosis-item strong { display: block; margin-bottom: 3px; }
.diagnosis-item p { margin: 0; color: var(--muted); font-size: .9rem; }
.output-bottom { margin-top: 18px; padding: 16px; border-left: 3px solid var(--blue); background: var(--surface); }
.output-bottom strong { display: block; margin-bottom: 5px; }
.output-bottom p { margin: 0; color: var(--muted); }

.engine-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0 0; }
.engine-badge { display: inline-flex; align-items: center; gap: 7px; padding: 7px 10px; border: 1px solid var(--line); background: var(--surface); color: var(--muted); font-family: var(--mono); font-size: .73rem; font-weight: 700; }
.engine-badge .status-dot { width: 6px; height: 6px; box-shadow: none; }
.engine-badge.no .status-dot { background: var(--faint); }
.code-block {
  overflow-x: auto;
  margin: 20px 0;
  padding: 18px;
  border: 1px solid #bfccdb;
  background: #253449;
  color: #e7f0fb;
  font-family: var(--mono);
  font-size: .82rem;
  line-height: 1.6;
}

.site-footer { border-top: 1px solid var(--line); background: #eaf0f6; }
.footer-shell { width: min(var(--max), calc(100% - 40px)); margin: 0 auto; padding: 28px 0 36px; display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.footer-shell p { margin: 0; color: var(--muted); font-size: .82rem; }
.footer-links { display: flex; flex-wrap: wrap; gap: 8px 16px; font-size: .82rem; }

.not-found { display: grid; min-height: 100vh; place-items: center; padding: 20px; }
.not-found-card { width: min(540px, 100%); padding: 34px; border: 1px solid var(--line-strong); border-top: 4px solid var(--blue); background: var(--surface); box-shadow: var(--shadow); }
.not-found-card h1 { font-size: 2rem; }
.not-found-card .button { margin-top: 12px; }

:focus-visible { outline: 3px solid rgba(23, 105, 224, .35); outline-offset: 3px; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}
@media (max-width: 900px) {
  .header-shell { gap: 12px 20px; }
  .primary-nav { order: 3; flex-basis: 100%; margin-left: 0; padding-top: 3px; }
  .header-meta { margin-left: auto; }
  .hero { grid-template-columns: 1fr; gap: 28px; }
  .content-grid, .article-layout { grid-template-columns: 1fr; gap: 28px; }
  .side-note, .article-outline { position: static; }
  .process-grid { grid-template-columns: repeat(2, 1fr); }
  .process-step:nth-child(2) { border-right: 0; }
  .process-step:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
}
@media (max-width: 640px) {
  .header-shell, .page-shell, .footer-shell { width: min(100% - 28px, var(--max)); }
  .header-shell { min-height: 70px; }
  .brand { font-size: .9rem; }
  .header-meta { font-size: 9px; }
  .primary-nav { gap: 5px 10px; }
  .primary-nav a { font-size: 12px; }
  .breadcrumbs { padding-top: 20px; }
  .hero { padding: 34px 0 34px; }
  h1 { font-size: clamp(2.05rem, 11vw, 3.2rem); }
  h2 { font-size: 1.8rem; }
  .signal-strip, .fact-grid { grid-template-columns: 1fr; }
  .content-section { padding-top: 42px; }
  .rank-card { grid-template-columns: 38px minmax(0, 1fr); gap: 10px 12px; padding: 18px 14px; }
  .rank-tag { grid-column: 2; justify-self: start; }
  .rank-index { font-size: 1.2rem; }
  .process-grid { grid-template-columns: 1fr; }
  .process-step, .process-step:nth-child(2) { min-height: auto; border-right: 0; border-bottom: 1px solid var(--line); }
  .process-step:last-child { border-bottom: 0; }
  .diagnostic-shell { padding: 16px; }
  .question-card { grid-template-columns: 28px minmax(0, 1fr); padding: 14px; }
  .choice label { min-width: 70px; padding-inline: 8px; }
  .diagnostic-output { padding: 16px; }
  .output-header { flex-direction: column; }
  .code-block { font-size: .75rem; }
}