:root {
  --ink: #102a43;
  --muted: #52667a;
  --line: #d9e2ec;
  --paper: #ffffff;
  --soft: #f4f7fa;
  --accent: #0b6e69;
  --accent-dark: #075653;
  --accent-soft: #e5f5f2;
  --focus: #ffbf47;
  --danger: #a61b1b;
  --shadow: 0 14px 40px rgba(16, 42, 67, 0.10);
  --radius: 18px;
  --shell: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; line-height: 1.55; }
a { color: var(--accent-dark); text-underline-offset: 0.18em; }
a:hover { text-decoration-thickness: 2px; }
button, input, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
img, svg { max-width: 100%; }
.shell { width: min(100% - 32px, var(--shell)); margin-inline: auto; }
.narrow { max-width: 780px; }
.skip-link { position: fixed; left: 12px; top: 8px; z-index: 100; transform: translateY(-160%); background: var(--ink); color: white; padding: 10px 14px; border-radius: 8px; }
.skip-link:focus { transform: none; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }

.site-header { border-bottom: 1px solid var(--line); background: rgba(255,255,255,.96); position: sticky; top: 0; z-index: 20; }
.header-inner { min-height: 68px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 800; text-decoration: none; letter-spacing: -.02em; }
.brand-mark { width: 32px; height: 32px; display: grid; place-items: center; border-radius: 10px; background: var(--ink); color: white; font-size: 22px; line-height: 1; }
.primary-nav { display: none; gap: 20px; }
.primary-nav a { color: var(--ink); font-weight: 650; text-decoration: none; }

.hero, .page-hero, .calculator-hero { background: linear-gradient(180deg, #f4f8fb 0%, #ffffff 100%); }
.hero { padding: 58px 0 40px; }
.hero-grid { display: grid; gap: 28px; align-items: center; }
.eyebrow { margin: 0 0 10px; color: var(--accent-dark); font-weight: 800; text-transform: uppercase; letter-spacing: .12em; font-size: .78rem; }
h1, h2, h3, p { margin-top: 0; }
h1 { font-size: clamp(2.2rem, 9vw, 4.8rem); line-height: 1.02; letter-spacing: -.055em; max-width: 930px; margin-bottom: 20px; }
h2 { font-size: clamp(1.45rem, 4vw, 2.25rem); line-height: 1.15; letter-spacing: -.03em; }
.hero-copy, .page-hero p, .calculator-hero p { color: var(--muted); font-size: 1.08rem; max-width: 720px; }
.hero-actions { display: flex; flex-direction: column; gap: 10px; margin: 26px 0 22px; }
.button { min-height: 46px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; border-radius: 12px; border: 1px solid transparent; padding: 11px 16px; font-weight: 800; text-decoration: none; cursor: pointer; }
.button.primary { background: var(--accent); color: white; }
.button.primary:hover { background: var(--accent-dark); }
.button.secondary { background: var(--paper); color: var(--ink); border-color: var(--line); }
.button.text-button { background: transparent; color: var(--muted); }
.trust-row { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 8px 18px; color: var(--muted); font-size: .92rem; }
.trust-row li::before { content: "✓"; color: var(--accent); font-weight: 900; margin-right: 6px; }
.hero-demo { border: 1px solid var(--line); background: var(--paper); border-radius: 24px; padding: 24px; box-shadow: var(--shadow); }
.hero-demo h2 { font-size: 1.15rem; margin: 6px 0 18px; }
.demo-label { color: var(--muted); font-size: .82rem; text-transform: uppercase; letter-spacing: .1em; font-weight: 800; }
.demo-number { font-size: 3rem; font-weight: 900; letter-spacing: -.06em; }
.demo-number span { font-size: 1.2rem; color: var(--muted); }
.demo-sub { padding: 10px 0 18px; margin-bottom: 16px; border-bottom: 1px solid var(--line); color: var(--muted); }

.section { padding-top: 52px; padding-bottom: 52px; }
.soft-section { background: var(--soft); }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 22px; }
.section-heading h2 { margin-bottom: 4px; }
.section-heading p { color: var(--muted); margin-bottom: 0; }
.tool-grid { display: grid; gap: 12px; }
.tool-card { border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); overflow: hidden; }
.tool-card-link { min-height: 112px; display: grid; grid-template-columns: 44px 1fr auto; gap: 14px; align-items: center; padding: 18px; text-decoration: none; color: var(--ink); }
.tool-card-link:hover { background: var(--soft); }
.tool-icon { width: 42px; height: 42px; display: grid; place-items: center; border-radius: 12px; background: var(--accent-soft); color: var(--accent-dark); font-weight: 900; font-size: 1.25rem; }
.tool-card strong { display: block; font-size: 1.05rem; margin-bottom: 4px; }
.tool-card small { display: block; color: var(--muted); font-size: .9rem; line-height: 1.35; }
.arrow { font-size: 1.3rem; }
.principles-grid { display: grid; gap: 16px; }
.principles-grid article { padding: 22px; border-radius: var(--radius); background: var(--paper); border: 1px solid var(--line); }
.principles-grid span { color: var(--accent); font-weight: 900; }
.principles-grid h2 { font-size: 1.25rem; margin: 8px 0; }
.principles-grid p { color: var(--muted); margin-bottom: 0; }

.page-hero, .calculator-hero { padding: 44px 0 30px; border-bottom: 1px solid var(--line); }
.page-hero.compact { padding-bottom: 24px; }
.page-hero h1, .calculator-hero h1 { font-size: clamp(2.2rem, 8vw, 4rem); }
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 24px; font-size: .9rem; color: var(--muted); }
.breadcrumbs a { color: var(--muted); }

.calculator-section { padding-top: 28px; }
.calculator-layout { display: grid; gap: 18px; align-items: start; }
.calculator-card, .result-card, .content-card, .related-card { border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); padding: 20px; }
.calculator-card, .result-card { box-shadow: var(--shadow); }
.card-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding-bottom: 14px; margin-bottom: 18px; border-bottom: 1px solid var(--line); }
.card-heading h2 { font-size: 1.2rem; margin: 0; }
.card-heading span { color: var(--muted); font-size: .82rem; font-weight: 700; }
.form-grid { display: grid; gap: 14px; }
.field { display: grid; gap: 6px; font-weight: 700; font-size: .92rem; }
.input-wrap { position: relative; display: block; }
.field input, .field select { width: 100%; min-height: 48px; border: 1px solid #bcccdc; border-radius: 11px; background: white; color: var(--ink); padding: 10px 12px; }
.field input:focus, .field select:focus { border-color: var(--accent); }
.field .suffix { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--muted); font-weight: 600; pointer-events: none; }
.field input:has(+ .suffix) { padding-right: 62px; }
.advanced { margin-top: 16px; border-top: 1px solid var(--line); padding-top: 14px; }
.advanced summary { min-height: 44px; display: flex; align-items: center; cursor: pointer; font-weight: 800; color: var(--accent-dark); }
.advanced .form-grid { margin-top: 14px; }
.form-actions, .result-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 18px; }
.form-error { margin-top: 14px; padding: 12px; border-radius: 10px; background: #fff1f1; color: var(--danger); font-weight: 700; }
.results-list { margin: 0; }
.result-item { display: flex; justify-content: space-between; gap: 16px; align-items: baseline; padding: 13px 0; border-bottom: 1px solid var(--line); }
.result-item dt { color: var(--muted); }
.result-item dd { margin: 0; font-weight: 900; font-size: 1.25rem; text-align: right; }
.result-item dd small { color: var(--muted); font-size: .78rem; font-weight: 700; }
.result-item:nth-child(1) dd { color: var(--accent-dark); font-size: 1.65rem; }
.result-note { color: var(--muted); font-size: .84rem; margin: 16px 0 0; }
.result-actions span { color: var(--accent-dark); font-size: .85rem; font-weight: 700; }
.ad-slot { min-height: 90px; margin: 22px 0 0; display: grid; place-items: center; border: 1px dashed #9fb3c8; border-radius: 12px; background: var(--soft); color: var(--muted); font-size: .78rem; text-transform: uppercase; letter-spacing: .08em; text-align: center; padding: 12px; }
.article-grid { display: grid; gap: 18px; }
.prose { font-size: 1rem; }
.prose h2 { margin-top: 28px; font-size: 1.4rem; }
.prose h2:first-child { margin-top: 0; }
.prose p, .prose li { color: #334e68; }
.prose li + li { margin-top: 8px; }
.method-link { padding-top: 18px; border-top: 1px solid var(--line); }
.related-card h2 { font-size: 1.2rem; }
.related-card .tool-card + .tool-card { margin-top: 10px; }
.related-card .tool-card-link { min-height: 92px; padding: 13px; }
.faq-list details { border-bottom: 1px solid #bcccdc; }
.faq-list summary { min-height: 58px; display: flex; align-items: center; cursor: pointer; font-weight: 800; }
.faq-list p { color: var(--muted); padding-bottom: 18px; }

.site-footer { background: var(--ink); color: white; padding: 42px 0 20px; }
.footer-grid { display: grid; gap: 26px; }
.footer-brand { color: white; }
.footer-grid p { color: #bcccdc; max-width: 430px; margin-top: 12px; }
.footer-grid nav { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px 20px; }
.footer-grid nav a { color: white; }
.footer-bottom { border-top: 1px solid #334e68; margin-top: 28px; padding-top: 18px; display: flex; justify-content: space-between; gap: 14px; color: #bcccdc; font-size: .82rem; }

@media (min-width: 680px) {
  .primary-nav { display: flex; }
  .hero-actions { flex-direction: row; }
  .tool-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .principles-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .form-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: 1.3fr .7fr; }
}

@media (min-width: 900px) {
  .hero { padding: 82px 0 64px; }
  .hero-grid { grid-template-columns: minmax(0, 1.5fr) minmax(300px, .7fr); }
  .tool-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .calculator-layout { grid-template-columns: minmax(0, 1.35fr) minmax(310px, .65fr); }
  .result-card { position: sticky; top: 92px; }
  .article-grid { grid-template-columns: minmax(0, 1.4fr) minmax(300px, .6fr); }
}

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

.scope-note { max-width: 720px; margin-top: 14px; padding: 12px 16px; border-radius: 10px; background: color-mix(in srgb, var(--accent-dark) 10%, transparent); border: 1px solid color-mix(in srgb, var(--accent-dark) 30%, transparent); font-size: .95rem; }