:root {
  color-scheme: light;
  --bg: #f7f8fb;
  --surface: #ffffff;
  --surface-alt: #eef3f5;
  --text: #172026;
  --muted: #5b6872;
  --line: #d7e0e5;
  --accent: #1f6f78;
  --accent-dark: #164e55;
  --focus: #b94c2f;
  --shadow: 0 18px 50px rgba(23, 32, 38, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

a {
  color: var(--accent-dark);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--focus);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(247, 248, 251, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.top-nav {
  max-width: 1120px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  gap: 18px;
  justify-content: flex-end;
  flex-wrap: wrap;
}

.top-nav a {
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.top-nav a:hover {
  color: var(--accent-dark);
}

main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 54px 24px 72px;
}

.hero {
  padding: 64px 0 46px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent-dark);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  max-width: 1020px;
  margin: 0;
  font-size: clamp(30px, 4.6vw, 52px);
  line-height: 1.04;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: clamp(22px, 2.8vw, 34px);
  line-height: 1.15;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 8px;
  font-size: 18px;
  line-height: 1.25;
  letter-spacing: 0;
}

.lead {
  max-width: 760px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 18px;
}

.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: 10px 16px;
  border: 1px solid var(--accent);
  border-radius: 6px;
  color: var(--accent-dark);
  font-weight: 800;
  text-decoration: none;
}

.button.primary {
  color: #ffffff;
  background: var(--accent);
}

.button:hover {
  color: #ffffff;
  background: var(--accent-dark);
  border-color: var(--accent-dark);
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 1px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--line);
  box-shadow: var(--shadow);
}

.summary-grid article {
  min-height: 140px;
  padding: 22px;
  background: var(--surface);
}

.label {
  display: block;
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.summary-grid strong {
  display: block;
  font-size: 19px;
  line-height: 1.3;
}

.summary-grid p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.content-section {
  margin-top: 68px;
  padding-top: 36px;
  border-top: 1px solid var(--line);
}

.content-section > p {
  max-width: 860px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 17px;
}

.section-heading {
  max-width: 820px;
  margin-bottom: 18px;
}

.split {
  display: grid;
  grid-template-columns: minmax(240px, 0.8fr) minmax(0, 1.2fr);
  gap: 46px;
  align-items: start;
}

.item-list {
  display: grid;
  gap: 16px;
}

.testbed-section {
  display: grid;
  grid-template-columns: minmax(240px, 0.8fr) minmax(0, 1.2fr);
  gap: 46px;
  align-items: start;
}

.testbed-section .section-heading {
  margin-bottom: 22px;
}

.testbed-image {
  margin: 0;
}

.testbed-image img {
  width: 100%;
  display: block;
  border-radius: 8px;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.testbed-image figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 14px;
}

.testbed-copy p {
  margin: 0;
  color: var(--muted);
  font-size: 16px;
}

.testbed-copy > p {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.feature-list {
  display: grid;
  gap: 14px;
  margin-top: 20px;
}

.publication-list {
  display: grid;
  gap: 18px;
}

.item-list article,
.feature-list article,
.publication-card,
.data-card,
.timeline article,
.acknowledgment {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.item-list p,
.feature-list p,
.publication-card p,
.data-card p,
.timeline p,
.acknowledgment p {
  margin: 0;
  color: var(--muted);
}

.publication-card p + p {
  margin-top: 12px;
}

.publication-authors {
  font-weight: 700;
}

.publication-note {
  font-style: italic;
}

.publication-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
}

.publication-links a {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-alt);
  font-size: 14px;
  font-weight: 800;
  text-decoration: none;
}

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

.timeline article {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 18px;
}

.timeline span {
  width: 40px;
  height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  color: #ffffff;
  background: var(--accent);
  font-weight: 800;
}

.data-card {
  background: var(--surface-alt);
}

.contact-section {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  align-items: start;
}

.contact-section p {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 16px;
}

.contact-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

.acknowledgment {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(240px, 300px);
  gap: 24px;
  align-items: center;
  background: var(--surface-alt);
}

.nsf-logo {
  display: block;
  width: 100%;
  height: auto;
  margin: 0;
  border-radius: 6px;
}

footer {
  border-top: 1px solid var(--line);
  padding: 26px 24px;
  color: var(--muted);
  text-align: center;
}

footer p {
  margin: 0;
}

@media (max-width: 860px) {
  .top-nav {
    justify-content: flex-start;
  }

  main {
    padding-top: 28px;
  }

  .hero {
    padding-top: 36px;
  }

  .summary-grid,
  .testbed-section,
  .split,
  .contact-section {
    grid-template-columns: 1fr;
  }

  .acknowledgment {
    grid-template-columns: 1fr;
  }

  .contact-list {
    grid-template-columns: 1fr;
  }

  .nsf-logo {
    max-width: 260px;
  }

  .summary-grid article {
    min-height: 0;
  }
}

@media (max-width: 520px) {
  .top-nav {
    gap: 12px;
    padding: 12px 18px;
  }

  .top-nav a {
    font-size: 13px;
  }

  main {
    padding-left: 18px;
    padding-right: 18px;
  }

  .button {
    width: 100%;
  }

  .timeline article {
    grid-template-columns: 1fr;
  }
}