*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --teal: #1A6570;
  --teal-dark: #0D3D45;
  --teal-soft: #E3F4F6;
  --ink: #0D1C1F;
  --muted: #48616A;
  --faint: #7A9AA4;
  --surface: #F4F7F9;
  --card: #FFFFFF;
  --line: rgba(26,101,112,.12);
  --accent: #00BFA5;
  --shadow: 0 18px 48px rgba(13,61,69,.12);
}
html { scroll-behavior: smooth; }
body {
  font-family: 'DM Sans', sans-serif;
  background: var(--surface);
  color: var(--ink);
  line-height: 1.65;
}
a { color: inherit; }
.site-nav {
  min-height: 68px;
  padding: 0 6vw;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(255,255,255,.94);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(12px);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--teal);
  font-family: 'Sora', sans-serif;
  font-weight: 800;
}
.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: var(--teal);
  color: white;
  display: grid;
  place-items: center;
}
.nav-links { display: flex; align-items: center; gap: 24px; }
.nav-links a {
  text-decoration: none;
  color: var(--muted);
  font-size: .9rem;
  font-weight: 600;
}
.nav-links a:hover { color: var(--teal); }
.nav-cta {
  color: white !important;
  background: var(--teal);
  padding: 9px 18px;
  border-radius: 10px;
}
.breadcrumb {
  padding: 14px 8vw;
  background: white;
  border-bottom: 1px solid var(--line);
  display: flex;
  gap: 9px;
  align-items: center;
  flex-wrap: wrap;
  font-size: .84rem;
  color: var(--faint);
}
.breadcrumb a {
  color: var(--teal);
  text-decoration: none;
  font-weight: 700;
}
.breadcrumb a:hover { text-decoration: underline; }
.hero {
  min-height: 560px;
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) 360px;
  gap: 48px;
  align-items: center;
  padding: 86px 8vw;
  background:
    linear-gradient(135deg, rgba(13,61,69,.96), rgba(26,101,112,.92)),
    radial-gradient(circle at 78% 22%, rgba(0,191,165,.28), transparent 34%);
}
.hero-copy { max-width: 760px; }
.eyebrow, .section-kicker {
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: .11em;
  font-size: .78rem;
  font-weight: 800;
  margin-bottom: 12px;
}
h1, h2 {
  font-family: 'Sora', sans-serif;
  line-height: 1.12;
  letter-spacing: 0;
}
h1 {
  color: white;
  font-size: clamp(2.25rem, 5vw, 4.6rem);
  margin-bottom: 22px;
}
.lead {
  color: rgba(255,255,255,.78);
  font-size: 1.16rem;
  max-width: 680px;
}
.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 34px;
}
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 12px 20px;
  border-radius: 12px;
  text-decoration: none;
  font-weight: 800;
}
.button.primary { background: white; color: var(--teal); }
.button.secondary { border: 1px solid rgba(255,255,255,.32); color: white; }
.download-band .button.primary { background: var(--teal); color: white; }
.hero-card {
  background: rgba(255,255,255,.12);
  border: 1px solid rgba(255,255,255,.18);
  border-radius: 18px;
  padding: 28px;
  color: white;
  box-shadow: 0 24px 64px rgba(0,0,0,.18);
}
.card-label {
  display: block;
  color: rgba(255,255,255,.62);
  font-size: .82rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-bottom: 10px;
}
.hero-card strong {
  display: block;
  font-family: 'Sora', sans-serif;
  font-size: 1.55rem;
  line-height: 1.2;
}
.hero-card p { color: rgba(255,255,255,.72); margin-top: 12px; }
.mini-stat {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 22px;
}
.mini-stat span {
  background: rgba(255,255,255,.14);
  border-radius: 999px;
  padding: 7px 11px;
  font-size: .82rem;
  font-weight: 700;
}
.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 36px;
  max-width: 1120px;
  margin: 0 auto;
  padding: 76px 6vw 42px;
}
.article {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 38px;
  box-shadow: var(--shadow);
}
.toc {
  background: var(--teal-soft);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px;
  margin-bottom: 28px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}
.toc strong {
  color: var(--ink);
  margin-right: 6px;
}
.toc a {
  color: var(--teal);
  text-decoration: none;
  font-weight: 800;
  font-size: .9rem;
}
.toc a:hover { text-decoration: underline; }
.article h2, .faq-section h2, .related-section h2, .download-band h2 {
  font-size: clamp(1.45rem, 2.5vw, 2.1rem);
  margin-bottom: 16px;
}
.article h2:not(:first-of-type) { margin-top: 36px; }
.article p { color: var(--muted); margin-bottom: 14px; }
.benefit-list {
  margin: 18px 0 0 20px;
  color: var(--muted);
}
.benefit-list li { margin-bottom: 8px; }
.expert-block {
  background: #FBFDFD;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 22px;
  margin: 28px 0;
}
.expert-block h2 {
  margin-top: 0 !important;
}
.inline-download {
  display: inline-flex;
  margin-top: 10px;
  color: var(--teal);
  font-weight: 800;
}
.formula-table-wrap {
  overflow-x: auto;
  margin: 18px 0 4px;
}
.formula-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 620px;
  background: white;
  border: 1px solid var(--line);
}
.formula-table th,
.formula-table td {
  text-align: left;
  border-bottom: 1px solid var(--line);
  padding: 12px 14px;
  vertical-align: top;
}
.formula-table th {
  background: var(--teal-soft);
  color: var(--ink);
  font-family: 'Sora', sans-serif;
  font-size: .88rem;
}
.formula-table td {
  color: var(--muted);
  font-size: .92rem;
}
.example-list { display: grid; gap: 14px; margin-top: 18px; }
.example {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
  background: #FBFDFD;
}
.example span {
  display: inline-block;
  color: var(--teal);
  font-weight: 800;
  font-size: .82rem;
  margin-bottom: 6px;
}
.example strong { display: block; margin-top: 8px; color: var(--ink); }
.mistake-list {
  display: grid;
  gap: 10px;
  margin: 16px 0 28px 20px;
  color: var(--muted);
}
.mistake-list li { padding-left: 4px; }
.app-shot {
  margin: 30px 0;
  background: #FBFDFD;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px;
}
.app-shot img {
  display: block;
  width: min(100%, 360px);
  height: auto;
  margin: 0 auto;
  border-radius: 18px;
  box-shadow: 0 18px 42px rgba(13,61,69,.16);
}
.app-shot figcaption {
  margin-top: 14px;
  color: var(--faint);
  font-size: .88rem;
  text-align: center;
}
.side-panel {
  align-self: start;
  position: sticky;
  top: 92px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 22px;
}
.side-panel h2 { font-size: 1rem; margin-bottom: 12px; }
.side-panel a {
  display: block;
  text-decoration: none;
  color: var(--muted);
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-weight: 700;
}
.side-panel a:last-child { border-bottom: 0; }
.side-panel a:hover { color: var(--teal); }
.faq-section, .related-section, .download-band {
  max-width: 1120px;
  margin: 0 auto;
  padding: 42px 6vw;
}
.cluster-section {
  max-width: 1120px;
  margin: 0 auto;
  padding: 42px 6vw;
}
.cluster-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}
.cluster-block {
  background: white;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 20px;
}
.cluster-block h3 {
  font-family: 'Sora', sans-serif;
  font-size: 1rem;
  margin-bottom: 12px;
}
.cluster-links {
  display: grid;
  gap: 8px;
}
.cluster-links a {
  color: var(--teal);
  text-decoration: none;
  font-weight: 700;
  font-size: .92rem;
}
.cluster-links a:hover { text-decoration: underline; }
.faq-list { display: grid; gap: 12px; }
details {
  background: white;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px 20px;
}
summary {
  cursor: pointer;
  font-weight: 800;
  color: var(--ink);
}
details p { margin-top: 12px; color: var(--muted); }
.related-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.related-links a {
  background: white;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
  text-decoration: none;
  color: var(--teal);
  font-weight: 800;
}
.download-band {
  margin-top: 36px;
  margin-bottom: 80px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  box-shadow: var(--shadow);
}
.download-band p:not(.eyebrow) { color: var(--muted); max-width: 620px; }
footer {
  background: var(--ink);
  color: rgba(255,255,255,.56);
  padding: 42px 8vw;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
}
.footer-brand {
  color: white;
  font-family: 'Sora', sans-serif;
  font-weight: 800;
}
.footer-links { display: flex; gap: 20px; flex-wrap: wrap; }
.footer-links a {
  color: rgba(255,255,255,.58);
  text-decoration: none;
  font-size: .88rem;
}
.footer-links a:hover { color: white; }
.footer-copy { font-size: .82rem; }
@media (max-width: 900px) {
  .hero, .content-grid { grid-template-columns: 1fr; }
  .hero-card, .side-panel { position: static; }
  .related-links, .cluster-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .nav-links { display: none; }
  .site-nav { padding: 0 5vw; }
  .breadcrumb { padding: 12px 6vw; }
  .hero { min-height: auto; padding: 62px 6vw; }
  .article { padding: 26px 20px; }
  .related-links, .cluster-grid { grid-template-columns: 1fr; }
  .download-band { align-items: flex-start; flex-direction: column; }
  footer { flex-direction: column; align-items: flex-start; }
}