:root {
  --navy-950: #000e1a;
  --navy-900: #002f4a;
  --navy-800: #0a3d5c;
  --navy-700: #31394d;
  --teal-600: #009384;
  --green-600: #00b050;
  --green-700: #009a46;
  --green-soft: #cdffda;
  --mint-50: #f0fdf4;
  --ink: #0f172a;
  --muted: #475569;
  --line: rgba(0, 47, 74, 0.12);
  --paper: #f7faf8;
  --white: #ffffff;
  --shadow: 0 18px 50px rgba(0, 14, 26, 0.12);
  --radius: 4px;
  --max: 1120px;
  --header-h: 72px;
  --font-display: "Libre Baskerville", Georgia, "Times New Roman", serif;
  --font-body: "IBM Plex Sans", "Segoe UI", sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(0, 179, 80, 0.08), transparent 55%),
    radial-gradient(900px 500px at 100% 0%, rgba(0, 147, 132, 0.1), transparent 50%),
    linear-gradient(180deg, #eef7f2 0%, var(--paper) 28%, #ffffff 100%);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--navy-900);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--teal-600);
}

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

.skip-link {
  position: absolute;
  left: 1rem;
  top: -100%;
  z-index: 1000;
  background: var(--white);
  color: var(--navy-900);
  padding: 0.6rem 0.9rem;
  border-radius: var(--radius);
}

.skip-link:focus {
  top: 1rem;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background: rgba(0, 14, 26, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(205, 255, 218, 0.12);
}

.header-inner {
  max-width: calc(var(--max) + 4rem);
  margin: 0 auto;
  padding: 0 1.25rem;
  height: 100%;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  text-decoration: none;
  color: var(--white);
  min-width: 0;
}

.brand:hover {
  color: var(--green-soft);
}

.brand-nsf {
  width: 40px;
  height: 40px;
  object-fit: contain;
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  min-width: 0;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand-award {
  font-size: 0.72rem;
  color: rgba(205, 255, 218, 0.75);
  letter-spacing: 0.04em;
}

.nav {
  justify-self: center;
}

.nav-list {
  list-style: none;
  display: flex;
  gap: 0.15rem;
  margin: 0;
  padding: 0;
}

.nav-list a {
  display: block;
  color: rgba(255, 255, 255, 0.86);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  padding: 0.55rem 0.75rem;
  border-radius: var(--radius);
  transition: color 180ms ease, background 180ms ease;
}

.nav-list a:hover,
.nav-list a.is-active {
  color: var(--white);
  background: rgba(0, 179, 80, 0.18);
}

.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius);
  width: 42px;
  height: 36px;
  padding: 0;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
}

.nav-toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--white);
}

.header-logos {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.uni-logo.vt {
  height: 28px;
  width: auto;
}

.uni-logo.ucla {
  height: 42px;
  width: auto;
}

/* Hero */
.hero {
  position: relative;
  min-height: calc(100vh - var(--header-h));
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 4.5rem 1.25rem 3.5rem;
  color: var(--white);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(115deg, rgba(0, 14, 26, 0.94) 0%, rgba(0, 47, 74, 0.88) 48%, rgba(0, 100, 72, 0.72) 100%),
    radial-gradient(circle at 18% 20%, rgba(0, 179, 80, 0.28), transparent 42%),
    radial-gradient(circle at 82% 70%, rgba(0, 147, 132, 0.35), transparent 46%),
    repeating-linear-gradient(
      -18deg,
      rgba(255, 255, 255, 0.035) 0 1px,
      transparent 1px 14px
    ),
    var(--navy-950);
  animation: heroShift 18s ease-in-out infinite alternate;
}

.hero-bg::after {
  content: "";
  position: absolute;
  inset: auto -10% -35% 35%;
  height: 70%;
  background:
    radial-gradient(ellipse at center, rgba(205, 255, 218, 0.14), transparent 65%);
  filter: blur(8px);
}

.hero-content {
  position: relative;
  max-width: var(--max);
  width: 100%;
  margin: 0 auto;
  z-index: 1;
}

.hero-brand {
  margin: 0 0 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--green-soft);
}

.hero h1 {
  margin: 0;
  max-width: 16ch;
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 5vw, 3.55rem);
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.hero-lead {
  margin: 1.35rem 0 0;
  max-width: 54ch;
  font-size: 1.08rem;
  color: rgba(255, 255, 255, 0.86);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0.7rem 1.15rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: transform 160ms ease, background 160ms ease, color 160ms ease, border-color 160ms ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--green-600);
  color: var(--white);
  border: 1px solid transparent;
}

.btn-primary:hover {
  background: var(--green-700);
  color: var(--white);
}

.btn-ghost {
  background: transparent;
  color: var(--white);
  border: 1px solid rgba(255, 255, 255, 0.35);
}

.btn-ghost:hover {
  border-color: var(--green-soft);
  color: var(--green-soft);
}

.hero-institutions {
  position: relative;
  z-index: 1;
  max-width: var(--max);
  width: 100%;
  margin: 3.5rem auto 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.hero-institutions .uni-logo.vt {
  height: 36px;
}

.hero-institutions .uni-logo.ucla {
  height: 54px;
}

/* Sections */
.section {
  padding: 5rem 1.25rem;
}

.section-alt {
  background:
    linear-gradient(180deg, rgba(240, 253, 244, 0.85), rgba(255, 255, 255, 0.92)),
    var(--mint-50);
  border-block: 1px solid var(--line);
}

.section-inner {
  max-width: var(--max);
  margin: 0 auto;
}

.section-head {
  max-width: 70ch;
  margin-bottom: 2.5rem;
}

.eyebrow {
  margin: 0 0 0.65rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--teal-600);
}

.section h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.2vw, 2.35rem);
  line-height: 1.25;
  color: var(--navy-950);
}

.section-lead {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.intro-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 2rem;
  align-items: start;
}

.prose h3,
.goals h3 {
  margin: 0 0 0.65rem;
  font-size: 1.05rem;
  color: var(--navy-900);
}

.prose h3 + p {
  margin-top: 0;
}

.prose p {
  color: var(--muted);
  margin: 0 0 1.25rem;
}

.goals {
  background: linear-gradient(160deg, var(--navy-900), var(--navy-800));
  color: var(--white);
  padding: 1.5rem 1.4rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.goals h3 {
  color: var(--green-soft);
  font-family: var(--font-display);
  margin-bottom: 1rem;
}

.goal-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.goal-list li {
  display: grid;
  gap: 0.2rem;
  padding-top: 0.85rem;
  border-top: 1px solid rgba(205, 255, 218, 0.18);
}

.goal-list li:first-child {
  padding-top: 0;
  border-top: 0;
}

.goal-list strong {
  color: var(--white);
  font-size: 0.98rem;
}

.goal-list span {
  color: rgba(255, 255, 255, 0.78);
  font-size: 0.92rem;
}

.award-line {
  margin: 2.5rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.95rem;
}

.figure-stack,
.results-stack,
.figure-pair {
  display: grid;
  gap: 1.5rem;
}

.figure-pair {
  grid-template-columns: 1fr 1fr;
}

.figure {
  margin: 0;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: 0 10px 30px rgba(0, 47, 74, 0.05);
}

.figure img {
  width: 100%;
  background: #fbfdfc;
}

.figure figcaption {
  margin-top: 0.85rem;
  font-size: 0.9rem;
  color: var(--muted);
}

/* Team — interaction containers, not decorative cards */
.team-grid {
  display: grid;
  gap: 2rem;
}

.person {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 1.35rem;
  align-items: start;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--line);
}

.person:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.person img {
  width: 180px;
  height: 180px;
  object-fit: cover;
  object-position: center top;
  border-radius: var(--radius);
  background: #dfe8e4;
}

.person h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--navy-950);
}

.person-role {
  margin: 0.35rem 0 0.75rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--teal-600);
}

.person-bio {
  margin: 0;
  color: var(--muted);
  font-size: 0.98rem;
}

/* Footer */
.site-footer {
  background: var(--navy-950);
  color: rgba(255, 255, 255, 0.82);
  padding: 2.75rem 1.25rem 2.25rem;
}

.footer-inner {
  max-width: var(--max);
  margin: 0 auto;
}

.footer-logos {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.footer-logos .uni-logo.ucla {
  height: 48px;
}

.footer-nsf {
  width: 56px;
  height: 56px;
  object-fit: contain;
}

.footer-text {
  margin: 0;
  max-width: 75ch;
  font-size: 0.9rem;
  line-height: 1.65;
}

.footer-meta {
  margin: 1.25rem 0 0;
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: rgba(205, 255, 218, 0.7);
}

/* Motion */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 700ms ease, transform 700ms ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.delay-1 {
  transition-delay: 90ms;
}

.delay-2 {
  transition-delay: 160ms;
}

.delay-3 {
  transition-delay: 230ms;
}

@keyframes heroShift {
  from {
    filter: saturate(1);
    transform: scale(1);
  }
  to {
    filter: saturate(1.08);
    transform: scale(1.03);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal,
  .reveal.is-visible {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .hero-bg,
  .btn:hover {
    animation: none;
    transform: none;
  }
}

/* Responsive */
@media (max-width: 920px) {
  .header-inner {
    grid-template-columns: 1fr auto;
  }

  .header-logos {
    display: none;
  }

  .intro-grid,
  .figure-pair {
    grid-template-columns: 1fr;
  }

  .person {
    grid-template-columns: 140px 1fr;
  }

  .person img {
    width: 140px;
    height: 140px;
  }
}

@media (max-width: 720px) {
  :root {
    --header-h: 64px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .nav-list {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    background: rgba(0, 14, 26, 0.98);
    padding: 0.75rem;
    border-bottom: 1px solid rgba(205, 255, 218, 0.12);
  }

  .nav.is-open .nav-list {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding-top: 3.25rem;
  }

  .hero h1 {
    max-width: none;
  }

  .hero-institutions {
    margin-top: 2.5rem;
  }

  .hero-institutions .uni-logo.vt {
    height: 28px;
  }

  .hero-institutions .uni-logo.ucla {
    height: 44px;
  }

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

  .person img {
    width: 160px;
    height: 160px;
  }

  .footer-logos {
    flex-wrap: wrap;
    justify-content: center;
  }
}