:root {
  --navy: #12355b;
  --blue: #2563eb;
  --green: #16a34a;
  --green-dark: #15803d;
  --text: #243240;
  --muted: #5a6775;
  --line: #d7e1ee;
  --soft: #f3f6fb;
  --soft-blue: #eaf1ff;
  --white: #ffffff;
  --shadow: 0 24px 55px rgba(18, 53, 91, 0.09);
  --radius: 24px;
  --radius-sm: 16px;
  --heading: "Avenir Next", "Gill Sans", "Trebuchet MS", sans-serif;
  --body: "Source Serif 4", Georgia, serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(circle at top right, rgba(37, 99, 235, 0.12), transparent 24%),
    radial-gradient(circle at left 20%, rgba(22, 163, 74, 0.08), transparent 22%),
    linear-gradient(180deg, #ffffff 0%, #f8fbff 44%, #f5f8fc 100%);
  font-family: var(--body);
  line-height: 1.72;
}

a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
img, svg { max-width: 100%; }
select, button, input, textarea { font: inherit; }

.container {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(18px);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(18, 53, 91, 0.08);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 82px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.95rem;
  color: var(--navy);
  text-decoration: none;
}

.brand strong,
h1,
h2,
h3,
h4 {
  font-family: var(--heading);
}

.brand small {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
}

.brand-mark {
  width: 50px;
  height: 50px;
  border-radius: 18px;
  background: linear-gradient(135deg, var(--navy), var(--blue));
  position: relative;
  box-shadow: var(--shadow);
}

.brand-mark::before,
.brand-mark::after {
  content: "";
  position: absolute;
  background: rgba(255, 255, 255, 0.92);
  border-radius: 999px;
}

.brand-mark::before {
  width: 22px;
  height: 6px;
  left: 14px;
  top: 14px;
}

.brand-mark::after {
  width: 16px;
  height: 6px;
  left: 14px;
  top: 26px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-link,
.nav-cta {
  font-family: var(--heading);
  font-size: 0.95rem;
  color: var(--navy);
}

.nav-cta {
  padding: 0.85rem 1.1rem;
  border-radius: 999px;
  background: var(--navy);
  color: var(--white);
  text-decoration: none;
}

.menu-toggle {
  display: none;
  border: 1px solid var(--line);
  background: var(--white);
  border-radius: 12px;
  padding: 0.65rem;
}

.menu-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--navy);
  margin: 4px 0;
}

.hero {
  padding: 3.8rem 0 2.1rem;
}

.hero-home {
  padding-top: 4.4rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 2rem;
  align-items: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.82rem;
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.11);
  color: var(--blue);
  font-family: var(--heading);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.03em;
}

.badge-hero { margin-bottom: 1rem; }

h1 {
  color: var(--navy);
  font-size: clamp(2.2rem, 4vw, 4.25rem);
  line-height: 1.06;
  margin: 0.2rem 0 1rem;
}

.hero-copy {
  color: var(--muted);
  font-size: 1.12rem;
  max-width: 64ch;
  margin: 0;
}

.hero-actions {
  display: flex;
  gap: 0.9rem;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0.92rem 1.18rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--heading);
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

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

.button-primary {
  background: var(--green);
  color: var(--white);
}

.button-primary:hover { background: var(--green-dark); }

.button-secondary {
  background: rgba(18, 53, 91, 0.05);
  color: var(--navy);
  border-color: rgba(18, 53, 91, 0.1);
}

.hero-card,
.dashboard-panel,
.stat-card,
.toc-card,
.sidebar-card,
.author-box,
.callout,
.related-card,
.topic-card,
.calculator-card,
.faq-list details,
.chart-card,
.table-shell,
.disclaimer-box {
  background: var(--white);
  border: 1px solid rgba(18, 53, 91, 0.08);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero-card,
.dashboard-panel {
  padding: 1.4rem;
}

.dashboard-panel {
  overflow: visible;
}

.hero-card-head,
.section-heading {
  margin-bottom: 1rem;
}

.eyebrow {
  display: inline-block;
  font-family: var(--heading);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  color: var(--blue);
  font-weight: 800;
}

.hero-card-row {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.95rem 0;
  border-top: 1px solid var(--line);
}

.hero-card-row:first-of-type { border-top: 0; }

.timeline-visual {
  margin-top: 1rem;
  display: grid;
  gap: 0.8rem;
}

.timeline-step span {
  display: block;
  margin-bottom: 0.35rem;
  font-family: var(--heading);
  font-size: 0.9rem;
  color: var(--muted);
}

.timeline-track {
  height: 10px;
  border-radius: 999px;
  background: #dce8f8;
  overflow: hidden;
}

.timeline-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--green), var(--blue));
  border-radius: inherit;
}

.dashboard {
  display: grid;
  gap: 1rem;
}

.dashboard-note {
  background: linear-gradient(135deg, rgba(18, 53, 91, 0.98), rgba(37, 99, 235, 0.92));
  color: var(--white);
}

.mini-chart {
  display: flex;
  align-items: end;
  gap: 0.9rem;
  height: 250px;
  margin-top: 1rem;
  padding-bottom: 2.6rem;
}

.mini-chart div {
  flex: 1;
  background: linear-gradient(180deg, var(--blue), var(--navy));
  border-radius: 18px 18px 8px 8px;
  position: relative;
  min-height: 84px;
}

.mini-chart span {
  position: absolute;
  bottom: -2rem;
  left: 50%;
  transform: translateX(-50%);
  font-family: var(--heading);
  color: var(--muted);
  font-size: 0.82rem;
  white-space: nowrap;
  line-height: 1.2;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.stat-card {
  padding: 1.2rem;
}

.stat-value {
  color: var(--navy);
  font-family: var(--heading);
  font-size: 1.72rem;
  font-weight: 800;
  margin: 0 0 0.25rem;
}

.stat-label {
  margin: 0;
  font-family: var(--heading);
}

.stat-card small { color: var(--muted); }

.main-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 1.5rem;
  padding-bottom: 4rem;
}

.content-column > * + * { margin-top: 1.5rem; }
.content-section,
.feature-section { margin-top: 1.5rem; }
.content-section p,
.content-section li { font-size: 1.05rem; }

.section-heading h2,
.author-box h2,
.sidebar-card h2,
.chart-card h2,
.faq-section h2 {
  color: var(--navy);
  margin: 0.15rem 0 0;
}

.section-intro {
  font-size: 1.08rem;
  color: var(--muted);
}

.callout { padding: 1.35rem; }

.intro-callout .callout {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.08), rgba(22, 163, 74, 0.08));
}

.key-takeaway ul,
.content-section ul,
.sidebar-card ul {
  padding-left: 1.2rem;
}

.toc-card,
.sidebar-card {
  padding: 1.2rem;
  position: sticky;
  top: 102px;
}

.toc-card ol {
  padding-left: 1.2rem;
  margin: 0;
}

.toc-card li + li { margin-top: 0.55rem; }

.sidebar-button {
  margin-top: 1rem;
  width: 100%;
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  list-style: none;
  padding: 0;
  margin: 0 0 1rem;
}

.breadcrumbs li {
  color: var(--muted);
  font-family: var(--heading);
  font-size: 0.9rem;
}

.breadcrumbs li:not(:last-child)::after {
  content: "/";
  margin-left: 0.55rem;
  color: rgba(90, 103, 117, 0.55);
}

.card-grid,
.related-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.topic-card,
.related-card {
  display: block;
  padding: 1.25rem;
  color: inherit;
}

.topic-card h3,
.related-card h3 {
  margin: 0.75rem 0 0.5rem;
  color: var(--navy);
}

.author-box {
  display: grid;
  grid-template-columns: 88px 1fr;
  gap: 1rem;
  padding: 1.35rem;
}

.author-avatar {
  width: 88px;
  height: 88px;
  border-radius: 24px;
  display: grid;
  place-items: center;
  color: var(--white);
  font-family: var(--heading);
  font-size: 1.4rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--blue), var(--navy));
}

.faq-list {
  display: grid;
  gap: 0.9rem;
}

.faq-list details {
  padding: 1rem 1.1rem;
}

.faq-list summary {
  cursor: pointer;
  font-family: var(--heading);
  font-weight: 700;
  color: var(--navy);
}

.table-shell {
  overflow-x: auto;
  padding: 1rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 640px;
}

caption {
  text-align: left;
  margin-bottom: 0.9rem;
  color: var(--navy);
  font-family: var(--heading);
  font-weight: 700;
}

th,
td {
  padding: 0.85rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

thead th { background: var(--soft); }

.chart-card { padding: 1.2rem; }

.bar-chart {
  display: grid;
  gap: 0.85rem;
}

.bar-row {
  display: grid;
  grid-template-columns: 150px 1fr 140px;
  gap: 0.8rem;
  align-items: center;
}

.bar-track {
  height: 14px;
  background: #e3edf9;
  border-radius: 999px;
  overflow: hidden;
}

.bar-fill {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--green), var(--blue));
}

.calculator-card { padding: 1.35rem; }

.calculator-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.calculator-form label {
  display: grid;
  gap: 0.45rem;
  font-family: var(--heading);
  color: var(--navy);
  font-weight: 700;
}

.calculator-form input,
.calculator-form select {
  width: 100%;
  min-height: 46px;
  border-radius: 14px;
  border: 1px solid var(--line);
  padding: 0.85rem;
  background: var(--white);
}

.calculator-form button { grid-column: 1 / -1; }

.calculator-result {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 18px;
  background: var(--soft);
  min-height: 80px;
}

.disclaimer-box {
  padding: 1.1rem 1.2rem;
  background: linear-gradient(135deg, rgba(18, 53, 91, 0.04), rgba(37, 99, 235, 0.06));
}

.cookie-banner {
  position: fixed;
  right: 1rem;
  bottom: 1rem;
  width: min(430px, calc(100% - 2rem));
  background: rgba(18, 53, 91, 0.97);
  color: var(--white);
  padding: 1.15rem;
  border-radius: 22px;
  box-shadow: var(--shadow);
  z-index: 60;
}

.cookie-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  align-items: center;
}

.cookie-actions a {
  color: var(--white);
  text-decoration: underline;
}

.site-footer {
  background: linear-gradient(180deg, rgba(18, 53, 91, 0.98), rgba(12, 30, 52, 1));
  color: rgba(255, 255, 255, 0.88);
  padding: 3rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr 1fr;
  gap: 1.5rem;
}

.site-footer h2 {
  margin-top: 0;
  color: var(--white);
  font-size: 1rem;
}

.site-footer a {
  display: block;
  color: rgba(255, 255, 255, 0.88);
  margin-top: 0.55rem;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1.5rem;
  margin-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.14);
}

@media (max-width: 980px) {
  .hero-grid,
  .main-grid,
  .footer-grid,
  .card-grid,
  .related-grid,
  .hero-stats {
    grid-template-columns: 1fr;
  }

  .site-nav {
    position: absolute;
    top: 78px;
    right: 1rem;
    left: 1rem;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 1rem;
    background: var(--white);
    border-radius: 18px;
    box-shadow: var(--shadow);
  }

  .site-nav.is-open { display: flex; }
  .menu-toggle { display: inline-block; }
  .toc-card,
  .sidebar-card { position: static; }
}

@media (max-width: 640px) {
  .container { width: min(100% - 1.2rem, 1180px); }
  .hero { padding-top: 2.6rem; }
  .calculator-form { grid-template-columns: 1fr; }
  .bar-row { grid-template-columns: 1fr; }
  .author-box { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; }
  .mini-chart {
    height: 230px;
    gap: 0.6rem;
    padding-bottom: 3rem;
  }
  .mini-chart span {
    font-size: 0.74rem;
    bottom: -2.15rem;
  }
}