:root {
  --ink: #102a43;
  --ink-soft: #486581;
  --muted: #566b82;
  --line: #d9e2ec;
  --paper: #f7f9fb;
  --white: #ffffff;
  --mint: #7ee2c3;
  --mint-dark: #0f6f5a;
  --coral: #c84f3c;
  --gold: #f5bc4b;
  --shadow: 0 24px 70px rgba(16, 42, 67, .14);
  --radius: 20px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; line-height: 1.55; }
a { color: inherit; }
button, input, select { font: inherit; }
button { cursor: pointer; }
.site-header { max-width: 1200px; margin: 0 auto; padding: 24px 28px; display: flex; justify-content: space-between; align-items: center; gap: 24px; }
.brand, .footer-brand { display: inline-flex; align-items: center; gap: 10px; font-size: 1.04rem; font-weight: 800; letter-spacing: -.04em; text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 30px; height: 30px; color: var(--ink); background: var(--mint); border-radius: 10px; font-size: 1.1rem; font-weight: 900; }
.brand-accent { color: var(--mint-dark); }
.site-header nav { display: flex; gap: 24px; font-size: .84rem; font-weight: 700; color: var(--ink-soft); }
.site-header nav a { text-decoration: none; }
.site-header nav a:hover, .text-button:hover { color: var(--mint-dark); }
.hero { position: relative; max-width: 1200px; margin: 0 auto; padding: 62px 28px 116px; display: grid; grid-template-columns: minmax(0, .9fr) minmax(420px, 1.1fr); align-items: center; gap: 76px; }
.hero::before { content: ""; position: absolute; z-index: -1; width: 470px; height: 470px; left: -180px; top: 20px; border-radius: 50%; background: rgba(126, 226, 195, .17); filter: blur(2px); }
.hero-copy { padding-bottom: 30px; }
.eyebrow, .section-kicker { margin: 0 0 16px; color: var(--mint-dark); text-transform: uppercase; letter-spacing: .14em; font-size: .7rem; font-weight: 900; }
.eyebrow { display: flex; align-items: center; gap: 9px; }
.eyebrow-dot { width: 8px; height: 8px; background: var(--coral); border-radius: 50%; box-shadow: 0 0 0 6px rgba(247, 121, 104, .13); }
h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 600px; margin-bottom: 22px; font-size: clamp(3.5rem, 7vw, 6.9rem); line-height: .94; letter-spacing: -.09em; font-weight: 850; }
.hero-lede { max-width: 480px; margin-bottom: 38px; color: var(--ink-soft); font-size: 1.1rem; }
.hero-notes { display: flex; flex-wrap: wrap; gap: 15px 22px; color: var(--ink-soft); font-size: .76rem; font-weight: 700; }
.hero-notes span { display: inline-flex; align-items: center; gap: 7px; }
.hero-notes strong { color: var(--coral); font-size: .68rem; }
.calculator-shell { position: relative; background: var(--white); border: 1px solid rgba(217, 226, 236, .7); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow); }
.calculator-heading { display: flex; justify-content: space-between; align-items: start; margin-bottom: 28px; }
.calculator-heading h2 { margin: 0; font-size: 1.65rem; letter-spacing: -.05em; }
.live-badge { display: inline-flex; align-items: center; gap: 7px; color: var(--mint-dark); font-size: .72rem; font-weight: 800; }
.live-badge span { width: 7px; height: 7px; border-radius: 50%; background: var(--mint-dark); box-shadow: 0 0 0 5px rgba(22, 132, 106, .12); }
.field-grid, .currency-row { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.currency-row { margin-top: 18px; grid-template-columns: minmax(0, 1fr) minmax(150px, .58fr); }
.field { display: block; min-width: 0; color: var(--ink); font-size: .84rem; font-weight: 800; }
.custom-code[hidden] { display: none; }
.field-hint { display: block; margin: 3px 0 9px; color: var(--muted); font-size: .68rem; font-weight: 600; }
.input-wrap { display: flex; align-items: center; border: 1px solid var(--line); border-radius: 12px; background: #fbfcfd; transition: border-color .2s, box-shadow .2s; }
.input-wrap:focus-within, select:focus, .field input:focus { border-color: var(--mint-dark); box-shadow: 0 0 0 4px rgba(126, 226, 195, .2); outline: 0; }
.input-prefix { padding-left: 14px; color: var(--muted); font-size: 1.05rem; font-weight: 700; }
input, select { width: 100%; border: 1px solid var(--line); border-radius: 12px; padding: 12px 13px; color: var(--ink); background: #fbfcfd; outline: 0; }
.input-wrap input { border: 0; background: transparent; border-radius: 12px; padding-left: 8px; }
select { appearance: none; background-image: linear-gradient(45deg, transparent 50%, var(--ink-soft) 50%), linear-gradient(135deg, var(--ink-soft) 50%, transparent 50%); background-position: calc(100% - 17px) 18px, calc(100% - 12px) 18px; background-size: 5px 5px, 5px 5px; background-repeat: no-repeat; padding-right: 35px; }
.field-error { display: block; min-height: 18px; margin-top: 5px; color: var(--coral); font-size: .7rem; font-weight: 700; }
.form-actions { display: flex; align-items: center; gap: 13px; margin-top: 6px; }
.button { border: 0; border-radius: 11px; padding: 13px 18px; font-weight: 850; transition: transform .2s, box-shadow .2s, background .2s; }
.button:hover { transform: translateY(-1px); }
.button-primary { flex: 1; color: var(--ink); background: var(--mint); box-shadow: 0 8px 18px rgba(126, 226, 195, .25); }
.button-primary:hover { background: #94ecd3; }
.button-ghost { color: var(--ink-soft); background: transparent; }
.form-status { min-height: 20px; margin: 8px 0 0; color: var(--coral); font-size: .76rem; font-weight: 700; }
.results { margin-top: 18px; padding: 20px; border: 1px solid rgba(126, 226, 195, .45); border-radius: 15px; background: #f2fcf8; }
.result-main { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-bottom: 17px; border-bottom: 1px solid rgba(126, 226, 195, .55); }
.result-label { margin: 0 0 5px; color: var(--ink-soft); font-size: .69rem; font-weight: 800; letter-spacing: .02em; }
.result-value { margin: 0; color: var(--ink); font-size: 2.35rem; line-height: 1; letter-spacing: -.06em; font-weight: 850; }
.result-pill { padding: 5px 10px; border-radius: 999px; font-size: .69rem; font-weight: 850; }
.result-pill.positive { color: var(--mint-dark); background: rgba(126, 226, 195, .35); }
.result-pill.negative { color: #ba3b2d; background: rgba(247, 121, 104, .17); }
.result-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 15px; padding: 17px 0 12px; }
.result-item strong { display: block; font-size: 1.25rem; letter-spacing: -.04em; }
.result-detail { color: var(--muted); font-size: .68rem; }
.result-actions { display: flex; gap: 22px; }
.text-button { padding: 0; border: 0; color: var(--ink-soft); background: transparent; font-size: .72rem; font-weight: 800; }
.text-button span { color: var(--mint-dark); }
.content-section { max-width: 1200px; margin: 0 auto; padding: 82px 28px; border-top: 1px solid var(--line); }
.split-section { display: grid; grid-template-columns: .8fr 1.2fr; gap: 90px; }
.section-intro h2 { max-width: 430px; margin: 0; font-size: clamp(2rem, 4vw, 3.7rem); line-height: 1.02; letter-spacing: -.08em; }
.body-copy { max-width: 620px; color: var(--ink-soft); font-size: 1.03rem; }
.steps { margin: 38px 0 0; padding: 0; list-style: none; display: grid; gap: 22px; }
.steps li { display: grid; grid-template-columns: 34px 1fr; gap: 13px; align-items: start; }
.steps li > span { display: grid; place-items: center; width: 29px; height: 29px; border: 1px solid var(--mint-dark); border-radius: 50%; color: var(--mint-dark); font-size: .75rem; font-weight: 900; }
.steps strong { color: var(--ink); font-size: .93rem; }
.steps p { margin: 4px 0 0; font-size: .85rem; }
.formula-list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 15px; margin-top: 38px; }
.formula-card { min-height: 225px; padding: 24px; border: 1px solid var(--line); border-radius: 15px; background: var(--white); }
.featured-formula { color: var(--white); background: var(--ink); border-color: var(--ink); }
.formula-number { display: block; margin-bottom: 42px; color: var(--coral); font-size: .7rem; font-weight: 900; }
.featured-formula .formula-number { color: #ff9b8a; }
.formula-card h3 { margin-bottom: 7px; font-size: 1rem; letter-spacing: -.02em; }
.formula-card p { min-height: 48px; margin-bottom: 18px; color: var(--ink-soft); font-size: .82rem; }
.featured-formula p { color: #bcccdc; }
.formula-card code { color: var(--mint-dark); font-size: .8rem; font-weight: 800; }
.featured-formula code { color: var(--mint); }
.formula-note { max-width: 760px; margin: 26px 0 0; color: var(--ink-soft); font-size: .83rem; }
.example-section { padding-top: 20px; }
.example-card { display: flex; align-items: center; justify-content: space-between; gap: 40px; padding: 40px 42px; border-radius: 18px; background: var(--mint); }
.example-card h2 { margin-bottom: 12px; font-size: clamp(1.8rem, 3vw, 2.7rem); letter-spacing: -.07em; }
.example-card p { max-width: 535px; margin: 0; color: #24594e; }
.example-equation { display: flex; align-items: center; gap: 12px; white-space: nowrap; color: #24594e; font-size: 1.2rem; font-weight: 800; }
.example-equation strong { color: var(--ink); font-size: 2rem; }
.faq-section { display: grid; grid-template-columns: .8fr 1.2fr; gap: 90px; }
.faq-list { border-top: 1px solid var(--line); }
details { border-bottom: 1px solid var(--line); }
summary { padding: 21px 0; color: var(--ink); font-weight: 850; cursor: pointer; list-style: none; display: flex; justify-content: space-between; gap: 20px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; color: var(--mint-dark); font-size: 1.2rem; line-height: 1; }
details[open] summary::after { content: "−"; }
details p { max-width: 650px; padding: 0 30px 21px 0; margin: 0; color: var(--ink-soft); font-size: .9rem; }
.site-footer { max-width: 1200px; margin: 0 auto; padding: 32px 28px 50px; display: flex; align-items: center; gap: 22px; border-top: 1px solid var(--line); color: var(--muted); font-size: .74rem; }
.site-footer .footer-brand { color: var(--ink); margin-right: auto; }
.site-footer p { margin: 0; }

@media (max-width: 850px) {
  .hero { grid-template-columns: 1fr; gap: 30px; padding-top: 34px; }
  .hero-copy { padding-bottom: 0; }
  .split-section, .faq-section { grid-template-columns: 1fr; gap: 35px; }
  .formula-list { grid-template-columns: 1fr; }
  .formula-card { min-height: auto; }
  .formula-number { margin-bottom: 20px; }
}
@media (max-width: 580px) {
  .site-header { padding: 18px 18px; }
  .site-header nav { display: none; }
  .hero, .content-section { padding-left: 18px; padding-right: 18px; }
  h1 { font-size: 4rem; }
  .calculator-shell { padding: 20px; border-radius: 15px; }
  .field-grid, .currency-row { grid-template-columns: 1fr; gap: 3px; }
  .currency-row { margin-top: 4px; }
  .form-actions { align-items: stretch; flex-direction: column; }
  .button-primary { flex: none; }
  .result-value { font-size: 2rem; }
  .example-card { padding: 27px 23px; display: block; }
  .example-equation { margin-top: 26px; }
  .site-footer { padding: 28px 18px 40px; align-items: flex-start; flex-direction: column; gap: 7px; }
  .site-footer .footer-brand { margin-right: 0; margin-bottom: 10px; }
}

/* Article and answer-first content */
.article-page { max-width: 920px; margin: 0 auto; padding: 64px 28px 110px; }
.article-header { max-width: 760px; margin-bottom: 38px; }
.article-header h1 { max-width: 760px; margin-bottom: 24px; font-size: clamp(2.8rem, 6vw, 5.8rem); }
.article-dek { max-width: 680px; color: var(--ink-soft); font-size: 1.18rem; }
.article-meta { margin: 24px 0 0; color: var(--muted); font-size: .78rem; font-weight: 700; }
.answer-box { margin: 0 0 48px; padding: 24px 28px; border-left: 5px solid var(--mint-dark); border-radius: 0 15px 15px 0; background: #eafaf4; }
.answer-box strong { color: var(--mint-dark); font-size: .76rem; letter-spacing: .08em; text-transform: uppercase; }
.answer-box p { max-width: 740px; margin: 8px 0 0; color: var(--ink); font-size: 1.04rem; }
.article-body { max-width: 720px; color: var(--ink-soft); font-size: 1.03rem; }
.article-body h2 { margin: 52px 0 14px; color: var(--ink); font-size: clamp(1.65rem, 3vw, 2.35rem); line-height: 1.08; letter-spacing: -.06em; }
.article-body p { margin-bottom: 20px; }
.article-body a { color: var(--mint-dark); font-weight: 800; }
.article-body strong { color: var(--ink); }
.article-body li { margin: 9px 0; padding-left: 4px; }
.definition-card { margin: 28px 0; padding: 20px 22px; border: 1px solid var(--line); border-radius: 13px; background: var(--white); }
.definition-card p { margin: 6px 0 0; }
.article-formula { padding: 18px 20px; border-radius: 11px; color: var(--ink); background: #edf2f7; overflow-x: auto; }
.article-formula code { font-size: .92rem; }
.article-table-wrap { margin: 26px 0; overflow-x: auto; }
.article-body table { width: 100%; border-collapse: collapse; font-size: .9rem; }
.article-body th, .article-body td { padding: 13px 15px; border-bottom: 1px solid var(--line); text-align: left; }
.article-body th { color: var(--ink); background: #edf2f7; font-size: .76rem; text-transform: uppercase; letter-spacing: .06em; }
.guide-promo { display: grid; grid-template-columns: .9fr 1.1fr; gap: 70px; align-items: center; }
.guide-promo p:not(.section-kicker) { color: var(--ink-soft); }
.guide-link { display: inline-flex; gap: 9px; align-items: center; color: var(--mint-dark); font-size: .9rem; font-weight: 850; text-decoration: none; }
.guide-link:hover { text-decoration: underline; }
@media (max-width: 700px) { .article-page { padding-top: 35px; } .guide-promo { grid-template-columns: 1fr; gap: 18px; } }