:root {
  --ink: #17243a;
  --ink-soft: #4c5a6d;
  --blue: #1769aa;
  --blue-dark: #0c4d82;
  --blue-deep: #09375e;
  --sky: #eaf4fb;
  --sky-2: #f4f9fc;
  --brass: #b7791f;
  --brass-soft: #fff4d9;
  --line: #d5e1ea;
  --paper: #ffffff;
  --canvas: #f5f8fa;
  --danger: #9a3412;
  --danger-soft: #fff0ea;
  --success: #276749;
  --success-soft: #edf8f2;
  --radius-sm: .55rem;
  --radius: .9rem;
  --radius-lg: 1.35rem;
  --shadow: 0 16px 42px rgba(15, 47, 76, .10);
  --max: 75rem;
  --measure: 47rem;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--canvas);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 1rem;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
}
img, svg { display: block; max-width: 100%; }
a { color: var(--blue-dark); text-decoration-thickness: .08em; text-underline-offset: .18em; }
a:hover { color: var(--blue-deep); }
a:focus-visible, summary:focus-visible { outline: .2rem solid #ffbf47; outline-offset: .2rem; border-radius: .2rem; }
h1, h2, h3 { color: var(--ink); font-weight: 750; line-height: 1.12; letter-spacing: -.025em; text-wrap: balance; }
h1 { margin: 0 0 1.25rem; font-size: clamp(2.35rem, 6vw, 4.65rem); }
h2 { margin: 3.25rem 0 1rem; font-size: clamp(1.7rem, 3vw, 2.45rem); }
h3 { margin: 2rem 0 .65rem; font-size: 1.25rem; }
p { margin: 0 0 1.1rem; }
ul, ol { margin: 0 0 1.35rem; padding-left: 1.35rem; }
li + li { margin-top: .45rem; }
strong { color: var(--ink); }
code { padding: .12rem .35rem; border-radius: .3rem; background: #edf1f5; font-size: .9em; }
.shell { width: min(calc(100% - 2rem), var(--max)); margin-inline: auto; }
.narrow { max-width: var(--measure); }
.section { padding-block: clamp(3.25rem, 7vw, 6rem); }
.section-compact { padding-block: 2.5rem; }
.section-blue { background: var(--sky); border-block: 1px solid var(--line); }
.section-white { background: var(--paper); }
.prose { max-width: var(--measure); }
.prose > :first-child { margin-top: 0; }
.lead { max-width: 44rem; color: var(--ink-soft); font-size: clamp(1.1rem, 2vw, 1.35rem); line-height: 1.55; }
.eyebrow { margin-bottom: .7rem; color: var(--blue-dark); font-size: .78rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.kicker { color: var(--brass); font-weight: 800; }
.muted { color: var(--ink-soft); }

.skip-link { position: fixed; top: .5rem; left: .5rem; z-index: 1000; transform: translateY(-160%); padding: .7rem 1rem; color: #fff; background: var(--blue-deep); }
.skip-link:focus { transform: translateY(0); }
.site-header { position: sticky; top: 0; z-index: 20; border-bottom: 1px solid rgba(213, 225, 234, .9); background: rgba(255, 255, 255, .95); backdrop-filter: blur(10px); }
.header-inner { min-height: 4.75rem; display: flex; align-items: center; justify-content: space-between; gap: 1.25rem; }
.brand { display: inline-flex; align-items: center; gap: .7rem; color: var(--ink); font-size: 1.06rem; font-weight: 850; text-decoration: none; letter-spacing: -.02em; }
.brand-mark { width: 2.35rem; height: 2.35rem; padding: .34rem; color: #fff; fill: none; stroke: currentColor; stroke-width: 2.5; background: var(--blue); border-radius: .7rem; }
.desktop-nav ul, .mobile-nav ul { display: flex; align-items: center; gap: .25rem; margin: 0; padding: 0; list-style: none; }
.desktop-nav a { display: block; padding: .65rem .72rem; color: var(--ink-soft); font-size: .89rem; font-weight: 700; text-decoration: none; border-radius: .5rem; }
.desktop-nav a:hover, .desktop-nav a[aria-current="page"] { color: var(--blue-dark); background: var(--sky); }
.mobile-nav { display: none; position: relative; }
.mobile-nav summary { cursor: pointer; padding: .6rem .8rem; color: var(--blue-dark); font-weight: 800; background: var(--sky); border-radius: .5rem; }
.mobile-nav nav { position: absolute; right: 0; top: calc(100% + .55rem); width: min(19rem, calc(100vw - 2rem)); padding: .8rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.mobile-nav ul { align-items: stretch; flex-direction: column; }
.mobile-nav a { display: block; padding: .65rem; font-weight: 700; text-decoration: none; }

.breadcrumbs { padding-top: 1.15rem; }
.breadcrumbs ol { display: flex; flex-wrap: wrap; gap: .45rem; margin: 0; padding: 0; list-style: none; color: var(--ink-soft); font-size: .85rem; }
.breadcrumbs li + li::before { content: "/"; margin-right: .45rem; color: #91a1b1; }
.page-hero { padding-block: clamp(3.75rem, 8vw, 6.5rem) clamp(2.75rem, 6vw, 4.5rem); }
.page-hero h1 { font-size: clamp(2.25rem, 5vw, 4.15rem); }
.home-hero { overflow: hidden; position: relative; padding-block: clamp(4.5rem, 9vw, 8rem); background: linear-gradient(135deg, #fff 0 57%, #eaf4fb 57% 100%); }
.home-hero::after { content: ""; position: absolute; right: -7rem; bottom: -9rem; width: 26rem; height: 26rem; border: 4.5rem solid rgba(23, 105, 170, .08); border-radius: 50%; }
.hero-grid { position: relative; z-index: 1; display: grid; grid-template-columns: minmax(0, 1.22fr) minmax(18rem, .78fr); gap: clamp(2.5rem, 6vw, 6rem); align-items: center; }
.hero-copy h1 { max-width: 52rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 1.7rem; }
.hero-note { margin-top: 1.5rem; color: var(--ink-soft); font-size: .9rem; }
.hero-visual { padding: 1.25rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg); box-shadow: var(--shadow); }
.hero-visual figcaption { margin-top: .8rem; color: var(--ink-soft); font-size: .85rem; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 2.9rem; padding: .75rem 1rem; color: #fff; font-weight: 800; text-decoration: none; background: var(--blue); border: 2px solid var(--blue); border-radius: .65rem; }
.button:hover { color: #fff; background: var(--blue-dark); border-color: var(--blue-dark); }
.button-secondary { color: var(--blue-dark); background: #fff; border-color: var(--line); }
.button-secondary:hover { color: var(--blue-deep); background: var(--sky); border-color: #aac8dc; }

.path-grid, .card-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem; }
.path-card, .info-card { position: relative; padding: 1.4rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.path-card { transition: transform .15s ease, box-shadow .15s ease; }
.path-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.path-card a::after { content: ""; position: absolute; inset: 0; }
.path-card .number { display: inline-grid; place-items: center; width: 2.15rem; height: 2.15rem; margin-bottom: 1rem; color: #fff; font-weight: 850; background: var(--blue); border-radius: .65rem; }
.path-card h2, .path-card h3, .info-card h3 { margin: 0 0 .6rem; font-size: 1.25rem; }
.path-card p, .info-card p { margin: 0; color: var(--ink-soft); }
.path-card a { font-weight: 800; }
.decision-steps { display: grid; gap: .9rem; margin: 2rem 0 0; padding: 0; list-style: none; counter-reset: steps; }
.decision-steps li { counter-increment: steps; display: grid; grid-template-columns: 2.6rem 1fr; gap: .9rem; align-items: start; padding: 1.1rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius-sm); }
.decision-steps li::before { content: counter(steps); display: grid; place-items: center; width: 2.3rem; height: 2.3rem; color: #fff; font-weight: 850; background: var(--blue-dark); border-radius: 50%; }
.decision-steps strong { display: block; margin-bottom: .2rem; }

.short-answer { margin: 1.75rem 0; padding: 1.25rem 1.35rem; color: var(--ink); background: var(--sky); border-left: .35rem solid var(--blue); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; }
.short-answer p:last-child { margin-bottom: 0; }
.warning, .good, .note { margin: 1.5rem 0; padding: 1.2rem 1.25rem; border-radius: var(--radius-sm); }
.warning { background: var(--danger-soft); border: 1px solid #f5c2ae; }
.warning strong { color: var(--danger); }
.good { background: var(--success-soft); border: 1px solid #b8dfc8; }
.good strong { color: var(--success); }
.note { background: var(--brass-soft); border: 1px solid #eed39b; }
.checklist { padding: 1.2rem 1.3rem 1.2rem 3rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.checklist li::marker { color: var(--success); content: "✓  "; font-weight: 900; }
.compare-table { width: 100%; margin: 1.5rem 0; border-collapse: collapse; background: #fff; border: 1px solid var(--line); }
.compare-table th, .compare-table td { padding: .85rem; text-align: left; vertical-align: top; border-bottom: 1px solid var(--line); }
.compare-table th { color: var(--blue-deep); background: var(--sky); }
.compare-table tr:last-child td { border-bottom: 0; }
.measurement-figure { margin: 2rem 0; padding: 1.2rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.measurement-figure figcaption { margin-top: .8rem; color: var(--ink-soft); font-size: .88rem; }
.measurement-protocol { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .75rem; margin: 1.4rem 0; }
.protocol-field { min-height: 4.8rem; padding: .8rem; background: #fff; border: 1px dashed #8aa5b9; border-radius: var(--radius-sm); }
.protocol-field strong { display: block; }
.affiliate-box { margin: 2.25rem 0; padding: 1.4rem; background: linear-gradient(135deg, var(--sky), #fff); border: 1px solid #b8d4e7; border-radius: var(--radius); }
.affiliate-kicker { margin: 0 0 .35rem; color: var(--blue-dark); font-size: .82rem; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; }
.button-amazon { margin-top: .25rem; background: var(--blue-deep); border-color: var(--blue-deep); }
.ad-label { margin: .65rem 0 0; color: var(--ink-soft); font-size: .78rem; }
.faq details { margin-bottom: .75rem; background: #fff; border: 1px solid var(--line); border-radius: var(--radius-sm); }
.faq summary { cursor: pointer; padding: 1rem 1.1rem; color: var(--ink); font-weight: 800; }
.faq details > div { padding: 0 1.1rem 1rem; color: var(--ink-soft); }
.source-list { padding-left: 1.1rem; font-size: .92rem; }
.source-list a { overflow-wrap: anywhere; }

.site-footer { color: #dceaf5; background: var(--blue-deep); }
.footer-grid { display: grid; grid-template-columns: 1.25fr 1fr .7fr; gap: 2.5rem; padding-block: 3.25rem; }
.footer-title { color: #fff; font-weight: 850; }
.site-footer p { max-width: 34rem; font-size: .9rem; }
.site-footer ul { margin: 0; padding: 0; list-style: none; }
.site-footer li + li { margin-top: .4rem; }
.site-footer a { color: #fff; }
.copyright { padding-block: 1rem; font-size: .8rem; border-top: 1px solid rgba(255,255,255,.16); }

@media (max-width: 62rem) {
  .desktop-nav { display: none; }
  .mobile-nav { display: block; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-visual { max-width: 38rem; }
  .path-grid, .card-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 42rem) {
  body { font-size: .98rem; }
  .shell { width: min(calc(100% - 1.25rem), var(--max)); }
  .home-hero { background: linear-gradient(180deg, #fff 0 70%, var(--sky) 70% 100%); }
  .path-grid, .card-grid, .measurement-protocol, .footer-grid { grid-template-columns: 1fr; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .button { width: 100%; }
  .compare-table { display: block; overflow-x: auto; }
  .brand span { font-size: .96rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}

@media print {
  @page { margin: 16mm; }
  body { color: #000; background: #fff; font-size: 11pt; }
  .site-header, .site-footer, .breadcrumbs, .affiliate-box, .hero-actions, .page-jumps, .no-print { display: none !important; }
  .shell, .narrow, .prose { width: 100%; max-width: none; }
  .page-hero, .section { padding: 0; }
  h1 { font-size: 24pt; }
  h2 { margin-top: 18pt; font-size: 17pt; }
  a { color: #000; text-decoration: none; }
  .measurement-figure, .measurement-protocol, .checklist, .warning, .note, .good { break-inside: avoid; border-color: #777; }
  .protocol-field { min-height: 20mm; }
}