:root {
  --ink: #17212b;
  --muted: #5e6875;
  --line: #dfe5ec;
  --soft: #f5f7fa;
  --blue: #1f5fae;
  --blue-dark: #143f78;
  --green: #267451;
  --gold: #a76412;
  --white: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--white);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.55;
}

a {
  color: var(--blue);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.shell {
  width: min(1160px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--line);
}

.nav {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 800;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  width: 36px;
  height: 36px;
  display: inline-grid;
  place-items: center;
  border-radius: 8px;
  background: var(--blue);
  color: var(--white);
  font-size: 13px;
  letter-spacing: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 8px 10px;
  border-radius: 6px;
  color: var(--muted);
  font-weight: 700;
  font-size: 14px;
}

.nav-links a.active,
.nav-links a:hover {
  color: var(--blue);
  background: #eaf2fb;
  text-decoration: none;
}

.hero {
  padding: 44px 0 34px;
  background: linear-gradient(180deg, #eef5fb 0%, #ffffff 100%);
}

.tool-hero {
  border-bottom: 1px solid var(--line);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 430px;
  gap: 30px;
  align-items: center;
}

.eyebrow {
  display: inline-block;
  color: var(--blue-dark);
  font-weight: 800;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0;
  margin-bottom: 12px;
}

h1,
h2,
h3 {
  line-height: 1.2;
  margin: 0 0 12px;
}

h1 {
  font-size: clamp(34px, 5vw, 58px);
  max-width: 820px;
}

h2 {
  font-size: 28px;
}

h3 {
  font-size: 18px;
}

.hero-copy,
.page-hero p {
  font-size: 18px;
  color: var(--muted);
  max-width: 720px;
  margin: 0;
}

.hero-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 22px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 10px 14px;
  border: 1px solid transparent;
  border-radius: 6px;
  font-weight: 800;
  cursor: pointer;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background: var(--blue);
  color: var(--white);
}

.btn-light {
  background: var(--white);
  color: var(--blue);
  border-color: var(--line);
}

.btn-dark {
  background: var(--ink);
  color: var(--white);
}

.btn-outline {
  border-color: var(--line);
  color: var(--blue);
  background: var(--white);
}

.full-btn {
  width: 100%;
  margin-top: 14px;
}

.calculator-panel {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
  box-shadow: 0 12px 32px rgba(17, 34, 51, 0.09);
}

.wide-panel {
  box-shadow: none;
}

.form-grid {
  display: grid;
  gap: 12px;
}

.helper-form-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

label {
  display: grid;
  gap: 6px;
  color: var(--ink);
  font-weight: 800;
  font-size: 14px;
}

select,
input {
  width: 100%;
  min-height: 44px;
  border: 1px solid #cbd5df;
  border-radius: 6px;
  padding: 9px 10px;
  color: var(--ink);
  background: var(--white);
  font: inherit;
}

.result-box {
  margin-top: 16px;
  padding: 16px;
  border-radius: 8px;
  background: #eef7f2;
  border: 1px solid #c9e3d5;
}

.result-box span {
  display: block;
  color: var(--green);
  font-weight: 800;
  font-size: 13px;
}

.result-box strong {
  display: block;
  font-size: 28px;
  margin: 4px 0;
}

.result-box p {
  margin: 0;
  color: var(--muted);
}

.upcoming-payments {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid #c9e3d5;
}

.upcoming-payments b {
  display: block;
  margin-bottom: 8px;
}

.upcoming-payments ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.upcoming-payments li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: baseline;
}

.upcoming-payments li span {
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.upcoming-payments li strong {
  margin: 0;
  font-size: 15px;
  text-align: right;
}

.fine {
  color: var(--muted);
  font-size: 13px;
}

.section {
  padding: 46px 0;
}

.section-tight {
  padding-top: 24px;
}

.section-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.muted {
  color: var(--muted);
}

.quick-grid,
.info-grid,
.rule-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.info-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.quick-grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.quick-card,
.rule-card,
.scenario-card,
.info-grid article,
.faq-item,
.source-band {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.quick-card {
  display: block;
  padding: 18px;
  color: var(--ink);
}

.quick-card:hover {
  border-color: var(--blue);
  text-decoration: none;
}

.quick-card span {
  color: var(--gold);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}

.quick-card p,
.rule-card p,
.info-grid p {
  margin: 0;
  color: var(--muted);
}

.rule-card {
  padding: 18px;
}

.rule-card span,
.scenario-card span {
  display: inline-block;
  color: var(--green);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.info-grid article {
  padding: 20px;
}

.scenario-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.scenario-card {
  padding: 18px;
  background: var(--white);
}

.metric-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  border-top: 1px solid var(--line);
}

.metric-row b {
  color: var(--muted);
  font-size: 14px;
}

.metric-row strong {
  text-align: right;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 760px;
}

.data-table th,
.data-table td {
  padding: 13px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.data-table th {
  background: var(--soft);
  color: var(--ink);
  font-size: 13px;
}

.data-table tr:last-child td {
  border-bottom: 0;
}

.page-hero {
  padding: 50px 0;
  background: #eef5fb;
  border-bottom: 1px solid var(--line);
}

.answer-strip {
  background: var(--ink);
  color: var(--white);
}

.answer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  padding: 18px 0;
}

.answer-grid div {
  display: grid;
  gap: 2px;
}

.answer-grid span {
  color: #d5dde7;
}

.source-band {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 20px;
  padding: 20px;
  background: var(--soft);
}

.source-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.source-list a {
  display: grid;
  gap: 3px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--white);
}

.source-list span {
  color: var(--muted);
  font-size: 13px;
}

.faq-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.faq-item {
  padding: 18px;
}

.faq-item p {
  margin: 0;
  color: var(--muted);
}

.site-footer {
  padding: 36px 0;
  border-top: 1px solid var(--line);
  background: var(--ink);
  color: var(--white);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 24px;
}

.site-footer p,
.site-footer .fine {
  color: #c6d0da;
}

.site-footer a {
  display: block;
  color: #e9f3ff;
  margin: 7px 0;
}

@media (max-width: 900px) {
  .hero-grid,
  .source-band,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .quick-grid,
  .info-grid,
  .rule-grid,
  .scenario-grid,
  .helper-form-grid,
  .answer-grid,
  .faq-list,
  .source-list {
    grid-template-columns: 1fr;
  }

  .section-head {
    display: grid;
  }
}

@media (max-width: 640px) {
  .nav {
    align-items: flex-start;
    flex-direction: column;
    padding: 12px 0;
  }

  .nav-links {
    width: 100%;
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 2px;
  }

  h1 {
    font-size: 34px;
  }

  h2 {
    font-size: 24px;
  }

  .hero,
  .page-hero {
    padding: 34px 0;
  }
}