:root {
  --ink: #10243f;
  --muted: #5f6f84;
  --line: #d8e1ec;
  --paper: #f4f8fd;
  --white: #ffffff;
  --teal: #1f6fbf;
  --teal-dark: #164f9f;
  --red: #d64045;
  --amber: #a83b45;
  --blue: #1f6fbf;
  --navy: #0b2344;
  --oxygen: #1f6fbf;
  --deoxy: #d64045;
  --shadow: 0 24px 60px rgba(16, 36, 63, 0.16);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}

a {
  color: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 14px clamp(18px, 4vw, 54px);
  background: rgba(248, 251, 250, 0.92);
  border-bottom: 1px solid rgba(217, 224, 223, 0.85);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  text-decoration: none;
  white-space: nowrap;
}

.brand small {
  padding-left: 2px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  font-size: 0.78rem;
  letter-spacing: 0;
}

nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px 18px;
  color: var(--muted);
  font-size: 0.92rem;
}

nav a {
  text-decoration: none;
}

nav a:hover {
  color: var(--teal-dark);
}

.nav-button {
  padding: 5px 10px;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  font-weight: 800;
}

.nav-button:hover {
  color: white;
  background: var(--teal-dark);
}

.hero {
  position: relative;
  min-height: 92vh;
  display: grid;
  align-items: center;
  overflow: hidden;
  background: #07172d;
}

.hero img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(7, 18, 22, 0.9) 0%, rgba(7, 18, 22, 0.72) 39%, rgba(7, 18, 22, 0.2) 78%);
}

.hero-content {
  position: relative;
  max-width: 780px;
  padding: 72px clamp(22px, 7vw, 96px) 118px;
  color: white;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--teal);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero .eyebrow {
  color: #9ecbff;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.04;
  letter-spacing: 0;
}

h1 {
  max-width: 680px;
  font-size: clamp(3rem, 7vw, 6.8rem);
}

h2 {
  font-size: clamp(2rem, 4vw, 4rem);
}

h3 {
  font-size: 1.22rem;
}

p {
  margin: 14px 0 0;
}

.lede {
  max-width: 680px;
  color: rgba(255, 255, 255, 0.86);
  font-size: clamp(1.08rem, 2vw, 1.35rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 11px 18px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.32);
  font-weight: 800;
  text-decoration: none;
}

.button.primary {
  background: #f2f7ff;
  color: #0b2344;
}

.button.ghost {
  color: white;
}

.container {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
}

.section,
.band {
  padding: clamp(64px, 9vw, 120px) 0;
}

.band {
  background: var(--white);
}

.intro-band {
  border-bottom: 1px solid var(--line);
}

.two-col {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.9fr);
  gap: clamp(28px, 6vw, 72px);
  align-items: center;
}

.signal-panel,
.curve-card,
.card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
  box-shadow: 0 12px 32px rgba(20, 32, 37, 0.07);
}

.signal-panel {
  padding: clamp(22px, 4vw, 36px);
}

.readout {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.readout span {
  color: var(--muted);
  font-weight: 800;
}

.readout strong {
  color: var(--oxygen);
  font-size: clamp(3rem, 6vw, 5.2rem);
  line-height: 0.9;
  font-variant-numeric: tabular-nums;
}

.section-heading {
  max-width: 860px;
  margin-bottom: 34px;
}

.cards {
  display: grid;
  gap: 18px;
}

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

.card {
  padding: 24px;
}

.card.accent {
  background: #eaf3ff;
  border-color: #adcdf3;
}

.feature-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-top: 18px;
}

.feature-strip > div {
  padding: 26px;
  border-left: 5px solid var(--teal);
  background: white;
}

.masimo-endorsement {
  margin-top: 18px;
  padding: clamp(24px, 4vw, 36px);
  border-radius: 8px;
  background: var(--navy);
  color: white;
}

.masimo-endorsement .eyebrow {
  color: #9ecbff;
}

.masimo-endorsement p:not(.eyebrow) {
  max-width: 900px;
  color: rgba(255, 255, 255, 0.82);
  font-size: 1.06rem;
}

.light-diagram {
  min-height: 430px;
  position: relative;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: #edf4fc;
  border: 1px solid var(--line);
  overflow: hidden;
}

.clip {
  position: absolute;
  left: 50%;
  width: 180px;
  margin-left: -90px;
  padding: 14px;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  text-align: center;
  font-weight: 800;
}

.clip.top {
  top: 42px;
}

.clip.bottom {
  bottom: 42px;
}

.finger {
  width: min(72%, 360px);
  height: 132px;
  border-radius: 60px;
  background: linear-gradient(90deg, #d99074, #f2b299 45%, #c97d68);
  box-shadow: inset 0 0 28px rgba(83, 31, 22, 0.18);
}

.beam {
  position: absolute;
  left: 50%;
  width: 16px;
  height: 120px;
  margin-left: -8px;
  opacity: 0.8;
}

.beam.red {
  top: 102px;
  background: linear-gradient(#ff4e4b, transparent);
}

.beam.infrared {
  bottom: 102px;
  background: linear-gradient(transparent, #8bc7ff);
}

.curve-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(300px, 0.9fr);
  gap: 24px;
  align-items: stretch;
}

.anesthesia-section {
  background: #eef4fb;
}

.anesthesia-grid {
  display: grid;
  grid-template-columns: minmax(300px, 0.82fr) minmax(0, 1.18fr);
  gap: 24px;
  align-items: stretch;
}

.vintage-photo {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
  box-shadow: var(--shadow);
}

.vintage-photo img {
  display: block;
  width: 100%;
  min-height: 360px;
  object-fit: cover;
  object-position: center;
}

.vintage-photo figcaption {
  padding: 18px;
  color: var(--muted);
}

.vintage-photo figcaption strong {
  display: block;
  color: var(--ink);
  margin-bottom: 4px;
}

.safety-copy {
  display: grid;
  gap: 14px;
}

.safety-copy article {
  padding: 24px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: white;
}

.related-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.related-links a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 11px 16px;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  font-weight: 800;
  text-decoration: none;
}

.related-links a:hover {
  background: var(--teal-dark);
}

.curve-card {
  padding: 20px;
}

svg {
  width: 100%;
  height: auto;
}

svg line,
svg path {
  fill: none;
  stroke-linecap: round;
}

svg line {
  stroke: #839197;
  stroke-width: 2;
}

svg text {
  fill: var(--muted);
  font-size: 18px;
  font-weight: 700;
}

svg circle {
  fill: var(--amber);
}

.curve-main {
  stroke: var(--teal-dark);
  stroke-width: 7;
}

.curve-left {
  stroke: var(--blue);
  stroke-width: 3;
  stroke-dasharray: 8 10;
}

.curve-right {
  stroke: var(--red);
  stroke-width: 3;
  stroke-dasharray: 8 10;
}

.shift-list {
  display: grid;
  gap: 14px;
}

.shift-list article,
.cause-grid article {
  padding: 22px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 8px;
}

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

.factor-grid div {
  min-height: 150px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbff;
}

.factor-grid strong {
  display: block;
  margin-bottom: 8px;
  font-size: 1.3rem;
}

.factor-grid span {
  color: var(--muted);
}

.device-table {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

.device-table > div {
  display: grid;
  grid-template-columns: 0.7fr 1.2fr 1.2fr;
  border-top: 1px solid var(--line);
}

.device-table > div:first-child {
  border-top: 0;
}

.device-table span {
  padding: 18px;
}

.table-head {
  background: var(--navy);
  color: white;
  font-weight: 800;
}

.watch-callout {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  margin-top: 18px;
  padding: 24px;
  border-radius: 8px;
  border: 1px solid #adcdf3;
  background: #eaf3ff;
}

.text-link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 11px 16px;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  font-weight: 800;
  text-decoration: none;
}

.text-link:hover {
  background: var(--teal-dark);
}

.rainbow-panel {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(250px, 0.75fr);
  gap: 22px;
  align-items: center;
  margin-top: 18px;
  padding: 26px;
  border-radius: 8px;
  border: 1px solid #c9d8eb;
  background: linear-gradient(135deg, #fff, #f7fbfb);
}

.fine-print {
  color: var(--muted);
  font-size: 0.94rem;
}

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

.rainbow-metrics span {
  display: grid;
  min-height: 62px;
  place-items: center;
  border-radius: 8px;
  color: white;
  font-weight: 900;
}

.rainbow-metrics span:nth-child(1) { background: var(--deoxy); }
.rainbow-metrics span:nth-child(2) { background: #a83b45; }
.rainbow-metrics span:nth-child(3) { background: var(--oxygen); }
.rainbow-metrics span:nth-child(4) { background: var(--teal-dark); }
.rainbow-metrics span:nth-child(5) { background: #5c6a70; }
.rainbow-metrics span:nth-child(6) { background: var(--ink); }

.concentrator-buying {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.45fr);
  gap: 22px;
  align-items: center;
  margin-top: 18px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

.affiliate-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.45fr);
  gap: 22px;
  align-items: center;
  margin-top: 18px;
  padding: 24px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: white;
}

.affiliate-links {
  display: grid;
  gap: 10px;
}

.affiliate-links a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 11px 14px;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  font-weight: 800;
  text-align: center;
  text-decoration: none;
}

.affiliate-links a:hover {
  background: var(--teal-dark);
}

.newborn-band {
  background: #eef5ff;
}

.concentrator-band {
  background: #f1f6fc;
}

.photo-section {
  background: #eef3f9;
}

.photo-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.photo-card {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
  box-shadow: 0 14px 34px rgba(20, 32, 37, 0.08);
}

.photo-card.wide {
  grid-row: span 2;
}

.photo-card img {
  display: block;
  width: 100%;
  height: 380px;
  object-fit: cover;
  object-position: center;
}

.photo-card.wide img {
  height: 560px;
}

.photo-card figcaption {
  padding: 16px;
  color: var(--muted);
  font-size: 0.95rem;
}

.photo-card figcaption strong {
  display: block;
  color: var(--ink);
  margin-bottom: 4px;
}

.concentrator-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.concentrator-grid article {
  padding: 24px;
  border: 1px solid #c9d8eb;
  border-radius: 8px;
  background: white;
}

.device-icon {
  display: inline-grid;
  min-width: 48px;
  height: 38px;
  place-items: center;
  margin-bottom: 18px;
  padding: 0 10px;
  border-radius: 8px;
  background: var(--navy);
  color: white;
  font-size: 0.85rem;
  font-weight: 900;
}

.hyperoxia-section {
  background: #fff4f5;
}

.risk-board {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.risk-board article {
  padding: 24px;
  border: 1px solid #efc5c9;
  border-radius: 8px;
  background: white;
}

.risk-board .fire-card {
  background: #3b1118;
  color: white;
  border-color: #3b1118;
}

.risk-board .fire-card p {
  color: rgba(255, 255, 255, 0.82);
}

.timeline {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 28px;
}

.timeline div {
  padding: 18px 12px;
  border-radius: 8px;
  background: white;
  border: 1px solid #adcdf3;
  text-align: center;
}

.timeline strong,
.timeline span {
  display: block;
}

.timeline span {
  color: var(--oxygen);
  font-size: 1.25rem;
  font-weight: 900;
}

.birth-circulation {
  display: grid;
  grid-template-columns: minmax(260px, 0.42fr) minmax(0, 0.58fr);
  gap: 18px;
  align-items: center;
  margin: 0 0 28px;
  padding: 22px;
  border: 1px solid #adcdf3;
  border-radius: 8px;
  background: white;
}

.diagram-copy p {
  color: var(--muted);
}

.birth-circulation svg {
  min-height: 300px;
}

.birth-circulation text {
  fill: var(--ink);
  font-size: 16px;
  font-weight: 800;
}

.birth-circulation .diagram-title {
  fill: var(--oxygen);
  font-size: 22px;
}

.heart-shape {
  fill: #fff4f5;
  stroke: var(--deoxy);
  stroke-width: 4;
}

.placenta {
  fill: #fff0f1;
  stroke: #a83b45;
  stroke-width: 4;
}

.quiet-lung {
  fill: #edf2f8;
  stroke: #839197;
  stroke-width: 4;
}

.active-lung {
  fill: #eaf3ff;
  stroke: var(--oxygen);
  stroke-width: 4;
}

.blue-flow,
.red-flow,
.bypass-flow,
.closing-flow,
.label-line,
.divider {
  fill: none;
  stroke-linecap: round;
}

.blue-flow {
  stroke: var(--oxygen);
  stroke-width: 7;
  marker-end: url(#arrowBlue);
}

.red-flow {
  stroke: var(--deoxy);
  stroke-width: 7;
  marker-end: url(#arrowRed);
}

.bypass-flow {
  stroke: #a83b45;
  stroke-width: 5;
  stroke-dasharray: 9 9;
  marker-end: url(#arrowRed);
}

.closing-flow {
  stroke: #839197;
  stroke-width: 5;
  stroke-dasharray: 5 8;
}

.label-line {
  stroke: #839197;
  stroke-width: 2;
}

.divider {
  stroke: #d9e0df;
  stroke-width: 2;
}

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

.nehi-section {
  background: #f4f8fd;
}

.nehi-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(320px, 1.05fr);
  gap: 20px;
  align-items: stretch;
}

.nehi-main {
  padding: clamp(24px, 4vw, 36px);
  border-radius: 8px;
  background: var(--navy);
  color: white;
}

.nehi-main p {
  color: rgba(255, 255, 255, 0.82);
}

.nehi-cards {
  display: grid;
  gap: 14px;
}

.nehi-cards article {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

.sources-band {
  background: var(--navy);
  color: white;
}

.sources-band .eyebrow,
.sources-band p {
  color: #b9d7ff;
}

.source-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 24px;
  margin: 0;
  padding-left: 20px;
}

.source-list a {
  color: white;
}

.footer {
  padding: 28px 0;
  background: #081418;
  color: white;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  color: rgba(255, 255, 255, 0.72);
}

.footer a {
  color: white;
  font-weight: 800;
}

@media (max-width: 900px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  nav {
    justify-content: flex-start;
  }

  .hero {
    min-height: 820px;
  }

  .hero-overlay {
    background: linear-gradient(180deg, rgba(7, 18, 22, 0.86) 0%, rgba(7, 18, 22, 0.76) 58%, rgba(7, 18, 22, 0.4) 100%);
  }

  .two-col,
  .curve-grid,
  .anesthesia-grid,
  .nehi-grid,
  .feature-strip,
  .cards.three,
  .photo-grid,
  .concentrator-grid,
  .risk-board,
  .factor-grid,
  .cause-grid,
  .source-list {
    grid-template-columns: 1fr;
  }

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

  .birth-circulation {
    grid-template-columns: 1fr;
  }

  .device-table {
    display: grid;
    gap: 14px;
    border: 0;
    background: transparent;
  }

  .device-table > div,
  .device-table > div:first-child {
    grid-template-columns: 1fr;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: white;
    overflow: hidden;
  }

  .table-head {
    display: none !important;
  }

  .watch-callout {
    align-items: flex-start;
    flex-direction: column;
  }

  .rainbow-panel {
    grid-template-columns: 1fr;
  }

  .affiliate-panel {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .container {
    width: min(100% - 28px, 1180px);
  }

  .hero-content {
    padding: 52px 18px 94px;
  }

  h1 {
    font-size: 3rem;
  }

  .timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-inner {
    flex-direction: column;
  }

  .photo-card img,
  .photo-card.wide img {
    height: 420px;
  }
}