:root {
  --navy: #14213d;
  --navy-light: #1f2f57;
  --teal: #0d9488;
  --teal-light: #14b8a6;
  --bg: #f7f8fa;
  --card: #ffffff;
  --text: #232733;
  --muted: #5b6272;
  --border: #e5e8ee;
  --maxw: 980px;
  font-size: 16px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
}

a { color: var(--teal); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; display: block; border-radius: 8px; }

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header / Nav ---------- */
header.site-header {
  background: var(--navy);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 1px 8px rgba(0,0,0,0.15);
}

.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-weight: 700;
  font-size: 1.2rem;
  color: #fff;
  letter-spacing: 0.2px;
}
.brand:hover { text-decoration: none; opacity: 0.9; }
.brand small {
  display: block;
  font-weight: 400;
  font-size: 0.72rem;
  color: #b7c0d8;
  letter-spacing: 0.3px;
}

nav.main-nav ul {
  list-style: none;
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
}

nav.main-nav a {
  color: #dbe1ee;
  padding: 8px 14px;
  border-radius: 6px;
  font-size: 0.93rem;
  font-weight: 500;
  transition: background 0.15s, color 0.15s;
}

nav.main-nav a:hover,
nav.main-nav a.active {
  background: rgba(255,255,255,0.12);
  color: #fff;
  text-decoration: none;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: #fff;
  font-size: 1.5rem;
  cursor: pointer;
}

@media (max-width: 720px) {
  nav.main-nav {
    display: none;
    width: 100%;
  }
  nav.main-nav.open { display: block; }
  nav.main-nav ul {
    flex-direction: column;
    padding: 8px 0 16px;
  }
  .nav-toggle { display: block; }
  .nav-inner { flex-wrap: wrap; }
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  color: #fff;
  padding: 76px 0 68px;
  background:
    /* teal glow, upper right */
    radial-gradient(ellipse 60% 70% at 78% 22%, rgba(20,184,166,0.20), transparent 62%),
    /* violet counter-glow, lower left */
    radial-gradient(ellipse 55% 65% at 12% 92%, rgba(129,80,200,0.16), transparent 60%),
    /* honeycomb lattice */
    url("../assets/hero-lattice.svg"),
    /* base */
    linear-gradient(135deg, #0f1a33 0%, var(--navy) 42%, var(--navy-light) 78%, #263a66 100%);
  background-size: auto, auto, 62px 107px, auto;
  background-repeat: no-repeat, no-repeat, repeat, no-repeat;
}

/* Brillouin zone accent, right side */
.hero::before {
  content: "";
  position: absolute;
  top: 50%;
  right: -70px;
  width: 420px;
  height: 420px;
  transform: translateY(-50%);
  background: url("../assets/hero-bz.svg") center/contain no-repeat;
  opacity: 0.55;
  pointer-events: none;
}

/* fade into the page below */
.hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 90px;
  background: linear-gradient(to bottom, transparent, rgba(247,248,250,0.10));
  pointer-events: none;
}

.hero .wrap {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 44px;
  flex-wrap: wrap;
}

.hero-photo {
  width: 320px;
  height: 320px;
  border-radius: 50%;
  object-fit: cover;
  /* Framing of the crop. Lower the percentage to shift the visible area upward. */
  object-position: center 25%;
  background: #1f2f57;
  border: 6px solid rgba(255,255,255,0.16);
  box-shadow: 0 0 0 1px rgba(94,234,212,0.35), 0 10px 34px rgba(0,0,0,0.32);
  flex-shrink: 0;
}

@media (max-width: 1080px) {
  .hero::before { right: -150px; opacity: 0.35; }
  .hero-photo { width: 280px; height: 280px; }
}
@media (max-width: 780px) {
  .hero::before { display: none; }
  .hero-photo { width: 230px; height: 230px; }
  .hero .wrap { gap: 28px; }
}
.hero-text {
  flex: 1 1 380px;
  max-width: 600px;
}
.hero-text h1 {
  margin: 0 0 6px;
  font-size: 2.3rem;
  letter-spacing: -0.4px;
  text-shadow: 0 2px 14px rgba(0,0,0,0.28);
}
.hero-text .role {
  color: var(--teal-light);
  font-weight: 600;
  margin-bottom: 14px;
  font-size: 1.05rem;
}
.hero-text p {
  color: #cfd6e6;
  max-width: 640px;
  margin: 0;
}
.hero-links { margin-top: 18px; display: flex; gap: 10px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  padding: 9px 18px;
  border-radius: 6px;
  font-weight: 600;
  font-size: 0.9rem;
  background: var(--teal);
  color: #fff;
  transition: background 0.15s;
}
.btn:hover { background: var(--teal-light); text-decoration: none; }
.btn.outline {
  background: transparent;
  border: 1.5px solid rgba(255,255,255,0.4);
  color: #fff;
}
.btn.outline:hover { border-color: #fff; background: rgba(255,255,255,0.08); }

/* ---------- Sections ---------- */
main { padding: 48px 0 72px; }
section { margin-bottom: 52px; }
section h2 {
  font-size: 1.5rem;
  color: var(--navy);
  margin: 0 0 6px;
  border-bottom: 3px solid var(--teal);
  display: inline-block;
  padding-bottom: 6px;
}
section .section-intro {
  color: var(--muted);
  margin: 14px 0 24px;
  max-width: 760px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 22px 24px;
  margin-bottom: 18px;
  box-shadow: 0 1px 3px rgba(20,33,61,0.04);
}

.card h3 { margin-top: 0; color: var(--navy); font-size: 1.08rem; }

.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--teal);
  background: #e6f6f4;
  padding: 3px 9px;
  border-radius: 4px;
  margin-bottom: 10px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
@media (max-width: 780px) {
  .grid-3 { grid-template-columns: 1fr; }
}

/* Reference line under a research theme */
.refs {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
  font-size: 0.86rem;
  color: var(--muted);
}
.refs strong { color: var(--navy); font-weight: 600; }
.refs a { font-weight: 500; }

/* News list */
.news-list { list-style: none; margin: 0; padding: 0; }
.news-list li {
  display: flex;
  gap: 16px;
  padding: 11px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.94rem;
}
.news-list li:last-child { border-bottom: none; }
.news-date {
  flex: 0 0 78px;
  font-weight: 700;
  color: var(--teal);
  font-size: 0.85rem;
  padding-top: 1px;
}

/* ---------- Publications ---------- */
.pub {
  border-left: 3px solid var(--teal);
  padding: 4px 0 4px 18px;
  margin-bottom: 26px;
}
.pub .pub-num { color: var(--muted); font-weight: 700; margin-right: 6px; }
.pub h3 { margin: 0 0 4px; font-size: 1.02rem; color: var(--navy); }
.pub .authors { color: var(--muted); font-size: 0.92rem; margin-bottom: 4px; }
.pub .venue { font-size: 0.88rem; margin-bottom: 8px; }
.pub .venue a { font-weight: 600; }
.pub .abstract { font-size: 0.93rem; color: #454b5a; }
.pub .badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  color: #a8580c;
  background: #fef1e2;
  padding: 2px 7px;
  border-radius: 4px;
  margin-left: 6px;
  vertical-align: middle;
}
.pub-group-label {
  text-transform: uppercase;
  font-size: 0.8rem;
  letter-spacing: 0.6px;
  font-weight: 700;
  color: var(--muted);
  margin: 30px 0 14px;
}
.profile-links { margin: 10px 0 30px; display: flex; gap: 14px; }
.profile-links a {
  font-weight: 600;
  background: #eef1f7;
  padding: 8px 16px;
  border-radius: 6px;
  color: var(--navy);
}
.profile-links a:hover { background: #e2e7f2; text-decoration: none; }

/* ---------- Timeline (Academic Background) ---------- */
.timeline { position: relative; padding-left: 26px; border-left: 2px solid var(--border); }
.timeline-item { margin-bottom: 34px; position: relative; }
.timeline-item::before {
  content: "";
  position: absolute;
  left: -32px;
  top: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--teal);
  border: 2px solid #fff;
  box-shadow: 0 0 0 2px var(--teal);
}
.timeline-item h3 { margin: 0 0 2px; color: var(--navy); }
.timeline-item .dates { color: var(--muted); font-size: 0.88rem; margin-bottom: 6px; }
.timeline-item .meta { font-size: 0.92rem; }
.timeline-item .meta div { margin-bottom: 2px; }

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
@media (max-width: 700px) {
  .contact-grid { grid-template-columns: 1fr; }
}
.contact-item { margin-bottom: 14px; }
.contact-item .label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--muted);
  font-weight: 700;
}
.contact-item .value { font-size: 1rem; }
iframe.map { width: 100%; height: 260px; border: 0; border-radius: 10px; }

/* ---------- Footer ---------- */
footer {
  background: var(--navy);
  color: #b7c0d8;
  padding: 28px 0;
  font-size: 0.85rem;
  text-align: center;
}
footer a { color: #dbe1ee; }