:root {
  --navy: #0b2265;
  --blue: #1f47c9;
  --sky: #3b8fe0;
  --ink: #1c2540;
  --muted: #5b6684;
  --line: #e3e8f3;
  --bg: #ffffff;
  --bg-soft: #f4f7fc;
  --radius: 18px;
  --nav-h: 72px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: var(--nav-h); }
body {
  margin: 0;
  font-family: "Plus Jakarta Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4 { color: var(--navy); line-height: 1.2; margin: 0 0 .5em; }
h2 { font-size: clamp(1.8rem, 3.4vw, 2.6rem); font-weight: 800; letter-spacing: -.02em; }
h3 { font-size: 1.35rem; font-weight: 700; }
h4 { font-size: 1.05rem; font-weight: 700; }
p { margin: 0 0 1em; }
a { color: inherit; }

.wrap { width: min(1200px, 100% - 32px); margin-inline: auto; }
.narrow { max-width: 820px; }
section { padding: 96px 0; }

.eyebrow {
  display: inline-block; font-size: .8rem; font-weight: 700; letter-spacing: .12em;
  text-transform: uppercase; color: var(--blue); margin-bottom: 12px;
}
.eyebrow.light { color: #9cc4ff; }
.section-head { max-width: 820px; margin-bottom: 48px; }
.section-head.center { text-align: center; margin-inline: auto; }
.section-head p { color: var(--muted); }
.sub { margin: 64px 0 24px; font-size: 1.15rem; text-transform: uppercase; letter-spacing: .08em; color: var(--blue); }
.muted { color: var(--muted); }

.btn {
  display: inline-flex; align-items: center; gap: 10px;
  background: var(--navy); color: #fff; text-decoration: none; border: 0; cursor: pointer;
  padding: 14px 28px; border-radius: 999px; font: inherit; font-weight: 600; font-size: .95rem;
  transition: background .2s, transform .2s;
}
.btn:hover { background: var(--blue); transform: translateY(-1px); }

/* ---------- NAV ---------- */
.nav {
  position: fixed; inset: 0 0 auto; height: var(--nav-h); z-index: 50;
  background: rgba(255,255,255,.85); backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent; transition: border-color .2s, box-shadow .2s;
}
.nav.scrolled { border-color: var(--line); box-shadow: 0 4px 20px rgba(11,34,101,.06); }
.nav-inner { height: 100%; display: flex; align-items: center; justify-content: space-between; }

.logo {
  font-size: 1.9rem; font-weight: 800; color: var(--navy); text-decoration: none;
  letter-spacing: -.02em; display: inline-flex; align-items: baseline;
}
.logo-a { position: relative; color: var(--navy); }
.logo-a svg {
  position: absolute; left: 50%; top: -.45em; width: 1.1em; transform: translateX(-50%);
  fill: none; stroke: var(--sky); stroke-width: 2.6; stroke-linecap: round;
}
.logo.small { font-size: 1.4rem; }

.menu { display: flex; gap: 34px; align-items: center; }
.menu a {
  text-decoration: none; font-weight: 600; font-size: .92rem; color: var(--ink);
  padding: 6px 0; border-bottom: 2px solid transparent; transition: color .2s, border-color .2s;
}
.menu a:hover, .menu a.active { color: var(--blue); border-color: var(--blue); }
.menu a.menu-cta { border: 1.5px solid var(--navy); border-radius: 999px; padding: 7px 18px; }
.menu a.menu-cta:hover, .menu a.menu-cta.active { background: var(--navy); color: #fff; }

.burger { display: none; background: none; border: 0; padding: 8px; cursor: pointer; }
.burger span { display: block; width: 24px; height: 2px; background: var(--navy); margin: 5px 0; transition: .25s; }

/* ---------- HERO ---------- */
.hero {
  position: relative; min-height: max(680px, 100vh); padding: calc(var(--nav-h) + 40px) 0 130px;
  background: #eef3fb url("assets/hero.jpg") right bottom / cover no-repeat;
  display: flex;
}
.hero::before { /* keeps headline readable over the sky on narrower screens */
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(90deg, rgba(255,255,255,.75) 0%, rgba(255,255,255,.35) 40%, rgba(255,255,255,0) 60%);
}
.hero-inner { position: relative; display: flex; flex-direction: column; justify-content: space-between; gap: 48px; }
.hero-text { max-width: 560px; margin-top: 6vh; }
.hero h1 { font-size: clamp(2.4rem, 5.2vw, 4.2rem); font-weight: 800; letter-spacing: -.03em; line-height: 1.05; }
.hero-text p { font-size: 1.15rem; font-weight: 500; color: var(--navy); max-width: 440px; margin-bottom: 28px; }

.hero-cards {
  display: grid; grid-template-columns: 1fr 1fr; max-width: 820px; margin-inline: auto; width: 100%;
  background: rgba(255,255,255,.88); backdrop-filter: blur(10px);
  border-radius: var(--radius); box-shadow: 0 12px 40px rgba(11,34,101,.12);
}
.hero-card { display: flex; gap: 18px; padding: 24px 28px; align-items: flex-start; }
.hero-card + .hero-card { border-left: 1px solid var(--line); }
.hero-card h3 { font-size: 1.1rem; margin-bottom: 4px; }
.hero-card p { margin: 0; font-size: .88rem; color: var(--muted); line-height: 1.5; }
.drop { width: 34px; flex: none; fill: none; stroke: var(--sky); stroke-width: 1.6; }

/* ---------- INTRO / BARRIERS ---------- */
.intro { padding: 96px 0 40px; }
.intro .lead { font-size: clamp(1.35rem, 2.4vw, 1.75rem); font-weight: 700; color: var(--navy); line-height: 1.4; }
.intro p { color: var(--muted); font-size: 1.08rem; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; }
.accent { font-size: 1.25rem; font-weight: 700; color: var(--blue); }

.stats-title { margin: 72px 0 28px; text-align: center; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.stat {
  background: var(--bg-soft); border-radius: var(--radius); padding: 32px;
  border: 1px solid var(--line);
}
.stat .num { font-size: 3.4rem; font-weight: 800; color: var(--navy); letter-spacing: -.03em; line-height: 1; margin-bottom: 14px; }
.stat .num span { color: var(--sky); }
.stat p { font-size: .92rem; color: var(--muted); margin: 0; }
.closing { max-width: 820px; margin: 48px auto 0; text-align: center; font-size: 1.1rem; font-weight: 600; color: var(--navy); }
.sources { text-align: center; font-size: .78rem; color: var(--muted); margin-top: 16px; }

/* ---------- TECHNOLOGY ---------- */
.tech { background: var(--bg-soft); }
.tech-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.tech-card {
  background: #fff; border-radius: var(--radius); padding: 40px;
  border: 1px solid var(--line); box-shadow: 0 8px 30px rgba(11,34,101,.05);
}
.tech-card p { color: var(--muted); }
.icon {
  width: 56px; height: 56px; border-radius: 14px; display: grid; place-items: center;
  background: linear-gradient(135deg, #e5efff, #d3e4ff); margin-bottom: 22px;
}
.icon svg { width: 30px; fill: none; stroke: var(--blue); stroke-width: 1.6; stroke-linecap: round; }
.band {
  margin-top: 28px; padding: 44px; border-radius: var(--radius); color: #dbe6ff;
  background: linear-gradient(120deg, var(--navy), var(--blue));
  display: grid; grid-template-columns: 1fr 1.2fr; gap: 48px;
}
.band h3 { color: #fff; font-size: 1.6rem; }
.band p:last-child { margin: 0; }

/* ---------- RESEARCH ---------- */
.timeline { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; position: relative; }
.timeline::before {
  content: ""; position: absolute; left: 0; right: 0; top: 15px; height: 2px;
  background: linear-gradient(90deg, var(--line), var(--sky));
}
.timeline li { position: relative; padding-top: 44px; }
.timeline li::before {
  content: ""; position: absolute; top: 8px; left: 0; width: 16px; height: 16px; border-radius: 50%;
  background: #fff; border: 3px solid var(--blue);
}
.timeline li.current::before { background: var(--blue); box-shadow: 0 0 0 6px rgba(31,71,201,.15); }
.timeline li.next::before { border-style: dashed; border-color: var(--sky); }
.step { font-size: .75rem; font-weight: 700; text-transform: uppercase; letter-spacing: .1em; color: var(--sky); }
.timeline h4 { margin: 6px 0 2px; }
.inst { display: block; font-size: .88rem; font-weight: 600; color: var(--blue); margin-bottom: 10px; }
.timeline p { font-size: .9rem; color: var(--muted); }

.pubs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.pub {
  display: block; text-decoration: none; padding: 28px; border-radius: var(--radius);
  border: 1px solid var(--line); background: #fff; transition: border-color .2s, transform .2s, box-shadow .2s;
}
.pub:hover { border-color: var(--sky); transform: translateY(-3px); box-shadow: 0 10px 30px rgba(11,34,101,.08); }
.pub-meta { font-size: .78rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--blue); }
.pub h4 { font-style: italic; font-weight: 600; margin: 10px 0; }
.pub-authors { font-size: .88rem; color: var(--muted); }

/* ---------- TEAM ---------- */
.team { background: var(--bg-soft); }
.people { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.person { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 20px; text-align: center; }
.person h4 { margin: 14px 0 2px; }
.person p { margin: 0; font-size: .88rem; color: var(--muted); }
.avatar {
  width: 170px; height: 170px; border-radius: 50%; font-size: 1.4rem; margin: 0 auto; display: grid; place-items: center;
  font-weight: 700; color: var(--blue); background: linear-gradient(135deg, #e5efff, #cfe0ff);
  background-size: cover; background-position: center;
}
.avatar.lg { flex: none; margin: 0; }
.leaders { display: grid; gap: 20px; }
.leader {
  display: flex; gap: 32px; align-items: flex-start; background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 32px;
}
.leader h4 { font-size: 1.25rem; margin-bottom: 2px; }
.role { display: block; font-weight: 600; color: var(--blue); }
.org { display: block; font-size: .88rem; color: var(--muted); margin-top: 2px; }
.leader p { margin: 12px 0 0; color: var(--muted); font-size: .95rem; }

/* ---------- LONDON ---------- */
.london { background: linear-gradient(135deg, #081a4f, var(--navy) 55%, #18379c); color: #c9d6f5; }
.london h2 { color: #fff; }

/* ---------- CONTACT ---------- */
.form { display: grid; gap: 16px; }
.form .row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form label { display: grid; gap: 6px; font-size: .85rem; font-weight: 600; color: var(--navy); }
.form input, .form textarea {
  font: inherit; font-weight: 400; color: var(--ink); padding: 12px 14px;
  border: 1px solid var(--line); border-radius: 12px; background: var(--bg-soft); resize: vertical;
}
.form input:focus, .form textarea:focus { outline: 2px solid var(--sky); outline-offset: 1px; background: #fff; }
.form .btn { justify-self: start; }
.form-status { margin: 0; font-size: .9rem; color: var(--blue); min-height: 1.4em; }

.footer { border-top: 1px solid var(--line); padding: 28px 0; font-size: .85rem; color: var(--muted); }
.footer-inner { display: flex; justify-content: space-between; align-items: center; gap: 16px; }

/* ---------- RESPONSIVE ---------- */
@media (max-width: 960px) {
  section { padding: 72px 0; }
  .two-col, .tech-grid, .band { grid-template-columns: 1fr; gap: 28px; }
  .stats, .pubs { grid-template-columns: 1fr; }
  .people { grid-template-columns: repeat(2, 1fr); }
  .timeline { grid-template-columns: 1fr; gap: 0; padding-left: 32px; }
  .timeline::before { left: 7px; right: auto; top: 0; bottom: 0; width: 2px; height: auto; background: linear-gradient(180deg, var(--line), var(--sky)); }
  .timeline li { padding: 0 0 28px; }
  .timeline li::before { left: -32px; top: 4px; }

  .burger { display: block; }
  .menu {
    position: fixed; top: var(--nav-h); left: 0; right: 0; flex-direction: column; gap: 0;
    background: #fff; border-bottom: 1px solid var(--line); padding: 8px 16px 20px;
    transform: translateY(-120%); transition: transform .3s; z-index: -1;
  }
  .menu.open { transform: none; }
  .menu a { width: 100%; padding: 14px 0; border-bottom: 1px solid var(--line); }
  .menu a.menu-cta { border: 0; border-radius: 0; padding: 14px 0; }
  .menu a.menu-cta:hover, .menu a.menu-cta.active { background: none; color: var(--blue); }
  .burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .hero { background-position: 70% bottom; min-height: 760px; }
  .hero::before { background: linear-gradient(180deg, rgba(255,255,255,.9) 0%, rgba(255,255,255,.55) 45%, rgba(255,255,255,0) 70%); }
  .hero-text { margin-top: 0; }
  .hero-cards { grid-template-columns: 1fr; }
  .hero-card + .hero-card { border-left: 0; border-top: 1px solid var(--line); }
  .people { grid-template-columns: 1fr 1fr; gap: 12px; }
  .avatar { width: 120px; height: 120px; }
  .leader { flex-direction: column; gap: 16px; padding: 24px; }
  .form .row { grid-template-columns: 1fr; }
  .tech-card, .band { padding: 28px; }
  .footer-inner { flex-direction: column; text-align: center; }
}