:root {
  --navy: #0a1a2f;
  --navy-deep: #071421;
  --navy-mid: #132a42;
  --green: #20d99a;
  --green-word: #20b982;
  --slate: #7d92a8;
  --text-slate: #52697e;
  --off-white: #f5f8fc;
  --page: #eef3f7;
  --line: #cbd8e2;
  --white: #ffffff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--page);
  color: var(--navy);
  font-family: Arial, "Nimbus Sans", "DejaVu Sans", sans-serif;
  font-size: 16px;
  line-height: 1.55;
}
a { color: inherit; }
a:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--green);
  outline-offset: 3px;
}

.container { width: min(1240px, calc(100% - 48px)); margin: 0 auto; }
.reading { max-width: 920px; }
.section { padding: 76px 0; }
.section-soft { background: var(--white); }
.section-dark { background: var(--navy); color: var(--off-white); }
.section h2,
.page-hero h1,
.hero h1 { letter-spacing: -0.035em; line-height: 1.08; }
.section h2 { font-size: clamp(32px, 3vw, 48px); margin: 0; }
.section h3 { line-height: 1.2; }
.eyebrow {
  color: var(--slate);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.14em;
  margin: 0 0 10px;
  text-transform: uppercase;
}
.eyebrow-green { color: var(--green-word); }

/* Header */
.site-header {
  background: var(--navy);
  position: sticky;
  top: 0;
  z-index: 10;
}
.header-inner {
  align-items: center;
  display: flex;
  justify-content: space-between;
  min-height: 70px;
  gap: 28px;
}
.brand { display: inline-flex; flex: 0 0 auto; }
.brand img { display: block; height: 46px; width: auto; }
.nav { display: flex; flex-wrap: wrap; gap: 8px 22px; }
.nav a {
  color: var(--off-white);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}
.nav a:hover,
.nav a[aria-current="page"] { color: var(--green); }

/* Hero */
.hero {
  background: var(--navy);
  color: var(--off-white);
  padding: clamp(72px, 10vw, 136px) 0;
}
.hero-grid {
  align-items: center;
  display: grid;
  gap: clamp(40px, 7vw, 120px);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.hero h1 { font-size: clamp(46px, 6.2vw, 82px); margin: 0; max-width: 800px; }
.hero-copy { color: #c6d3df; font-size: clamp(18px, 2vw, 22px); max-width: 650px; margin: 24px 0 32px; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  background: var(--green);
  border: 1px solid var(--green);
  border-radius: 8px;
  color: var(--navy);
  display: inline-block;
  font-weight: 700;
  padding: 12px 20px;
  text-decoration: none;
}
.btn:hover { background: #55e6b8; border-color: #55e6b8; }
.btn-ghost { background: transparent; color: var(--off-white); border-color: var(--slate); }
.btn-ghost:hover { background: transparent; border-color: var(--green); color: var(--green); }
.brand-showcase {
  display: flex;
  justify-content: flex-start;
}
.brand-showcase img {
  display: block;
  height: auto;
  max-width: 100%;
  width: min(100%, 520px);
}
.signal-path { align-items: center; display: flex; flex-wrap: wrap; gap: 10px; }
.signal-node { background: #203c55; border-radius: 999px; color: var(--off-white); font-weight: 700; padding: 8px 12px; }
.signal-node-active { background: var(--green); color: var(--navy); }
.signal-arrow { color: var(--green); font-size: 22px; }

/* Overview sections */
.intro-section { background: var(--page); }
.intro-grid { align-items: start; display: grid; gap: 64px; grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr); }
.intro-grid p:last-child { color: var(--text-slate); font-size: 19px; margin: 0; max-width: 710px; }
.section-heading { align-items: end; display: flex; gap: 36px; justify-content: space-between; margin-bottom: 30px; }
.section-heading > p { color: var(--text-slate); margin: 0; max-width: 430px; }
.section-heading-light > p { color: #c6d3df; }
.section-heading-light .eyebrow { color: var(--green); }

.band-grid,
.link-grid { display: grid; gap: 16px; }
.controls-grid,
.features-grid,
.link-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.modes-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.feature-band {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 14px;
  min-width: 0;
  overflow: hidden;
  padding: 22px;
  position: relative;
}
.feature-band::before { background: var(--band, var(--green)); content: ""; height: 8px; left: 0; position: absolute; right: 0; top: 0; }
.feature-band h3 { font-size: 21px; margin: 16px 0 8px; }
.feature-band p { margin: 0; }
.feature-band p + p { margin-top: 12px; }
.band-kicker { color: var(--band, var(--green-word)); font-size: 12px; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; }
.band-metric { color: var(--navy); font-size: 18px; font-weight: 700; }
.band-mint { --band: #20b982; background: #e9fcf5; }
.band-slate { --band: #6c8299; background: #edf2f6; }
.band-sky { --band: #1587bd; background: #e6f5fb; }
.band-navy { --band: #0a1a2f; background: #e9eef3; }
.inline-note { border-left: 4px solid var(--green-word); color: var(--text-slate); margin: 24px 0 0; padding-left: 14px; }

.mode-bypass { --band: #64748b; background: #f2f5f7; }
.mode-spectral { --band: #20b982; background: #e9fcf5; }
.mode-adaptive { --band: #1683b5; background: #e8f5fb; }
.best-use { border-top: 1px solid rgb(10 26 47 / 16%); margin-top: 20px !important; padding-top: 14px; }
.section-link { margin: 24px 0 0; }
.section-link a { color: var(--green-word); font-weight: 700; text-decoration: none; }
.section-link a:hover { text-decoration: underline; }

.feature-dark { --band: var(--green); background: var(--navy-mid); border-color: #28506c; color: var(--off-white); }
.feature-dark:nth-child(2) { --band: #65bfe8; }
.feature-dark:nth-child(3) { --band: #b9d2e3; }
.feature-dark:nth-child(4) { --band: #79d6b3; }
.feature-dark p { color: #c6d3df; }

.link-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  min-height: 188px;
  padding: 22px;
  text-decoration: none;
  transition: border-color 150ms ease, transform 150ms ease;
}
.link-card:hover { border-color: var(--green-word); transform: translateY(-3px); }
.link-card span { color: var(--green-word); font-size: 12px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; }
.link-card strong { font-size: 20px; line-height: 1.2; margin: 12px 0; }
.link-card small { color: var(--text-slate); font-size: 14px; }

/* Detail pages */
.page-hero { background: var(--navy); color: var(--off-white); padding: 76px 0; }
.page-hero h1 { font-size: clamp(42px, 5vw, 64px); margin: 0; max-width: 820px; }
.page-hero p:last-child { color: #c6d3df; font-size: 19px; margin: 18px 0 0; max-width: 720px; }
.subnav { background: var(--white); border-bottom: 1px solid var(--line); }
.subnav-inner { display: flex; gap: 20px; overflow-x: auto; padding: 14px 0; white-space: nowrap; }
.subnav a { color: var(--text-slate); font-size: 14px; font-weight: 700; text-decoration: none; }
.subnav a:hover { color: var(--green-word); }
.content-block + .content-block { margin-top: 52px; }
.content-block h2 { font-size: 30px; margin: 0 0 16px; }
.content-block h3 { font-size: 21px; margin: 28px 0 8px; }
.content-block p { max-width: 820px; }
.step-list { counter-reset: steps; display: grid; gap: 12px; list-style: none; margin: 24px 0 0; padding: 0; }
.step-list li { background: var(--white); border: 1px solid var(--line); border-radius: 10px; counter-increment: steps; padding: 16px 18px 16px 56px; position: relative; }
.step-list li::before { align-items: center; background: var(--navy); border-radius: 50%; color: var(--green); content: counter(steps); display: flex; font-size: 13px; font-weight: 700; height: 26px; justify-content: center; left: 17px; position: absolute; top: 17px; width: 26px; }
.detail-grid { display: grid; gap: 16px; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.detail-card { background: var(--white); border: 1px solid var(--line); border-radius: 12px; padding: 20px; }
.detail-card h3 { margin: 0 0 8px; }
.detail-card p { color: var(--text-slate); margin: 0; }
.notice { border-left: 5px solid var(--green-word); border-radius: 8px; margin: 24px 0; padding: 16px 18px; }
.notice p { margin: 0; }
.notice-warn { background: #fff6e5; border-left-color: #c97c19; color: #57380c; }
.notice-info { background: #e8f5fb; border-left-color: #1683b5; }
.table-wrap { border: 1px solid var(--line); border-radius: 12px; overflow-x: auto; }
.spec-table { border-collapse: collapse; min-width: 620px; width: 100%; }
.spec-table th,
.spec-table td { border-bottom: 1px solid var(--line); padding: 13px 16px; text-align: left; vertical-align: top; }
.spec-table th { background: #e8eef3; color: var(--text-slate); font-size: 13px; letter-spacing: 0.04em; text-transform: uppercase; width: 210px; }
.spec-table tr:last-child th,
.spec-table tr:last-child td { border-bottom: 0; }
.faq { display: grid; gap: 10px; }
.faq details { background: var(--white); border: 1px solid var(--line); border-radius: 10px; padding: 0 18px; }
.faq summary { cursor: pointer; font-weight: 700; padding: 17px 28px 17px 0; }
.faq details p { color: var(--text-slate); margin: 0 0 17px; }
.callout-links { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.callout-links a { border: 1px solid var(--line); border-radius: 999px; color: var(--green-word); font-size: 14px; font-weight: 700; padding: 8px 13px; text-decoration: none; }
.callout-links a:hover { border-color: var(--green-word); }

/* Footer */
.site-footer { background: var(--navy-deep); color: var(--slate); font-size: 14px; }
.footer-inner { align-items: center; display: flex; flex-wrap: wrap; gap: 10px 14px; min-height: 78px; }
.footer-inner img { display: block; }
.footer-inner a { color: var(--green); text-decoration: none; }
.footer-inner a:hover { text-decoration: underline; }

@media (max-width: 1040px) {
  .hero-grid,
  .intro-grid { grid-template-columns: 1fr; }
  .controls-grid,
  .features-grid,
  .link-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .modes-grid,
  .detail-grid { grid-template-columns: 1fr; }
  .section-heading { align-items: start; flex-direction: column; gap: 14px; }
}

@media (max-width: 640px) {
  .container { width: min(100% - 32px, 1240px); }
  .header-inner { align-items: flex-start; flex-direction: column; gap: 10px; padding: 14px 0; }
  .nav { flex-wrap: nowrap; max-width: 100%; overflow-x: auto; padding-bottom: 3px; width: 100%; }
  .hero { padding: 64px 0; }
  .section { padding: 56px 0; }
  .controls-grid,
  .features-grid,
  .link-grid { grid-template-columns: 1fr; }
  .hero-copy { font-size: 18px; }
  .page-hero { padding: 58px 0; }
  .step-list li { padding-left: 54px; }
}