:root {
  --bg: #ffffff;
  --bg-alt: #f4f7fb;
  --text: #1f2933;
  --muted: #667085;
  --line: #e4e7ec;
  --card: #ffffff;
  --accent: #222222;
  --accent-soft: #f0f0ef;
  --shadow: 0 14px 35px rgba(15, 23, 42, 0.06);
  --radius: 18px;
  --max-width: 1120px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}

a {
  color: inherit;
  text-decoration: none;
}

p {
  margin-bottom: 1rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.navbar {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 700;
  letter-spacing: -0.03em;
  font-size: 1.05rem;
}

.nav-links {
  display: flex;
  gap: 1.4rem;
  list-style: none;
  font-size: 0.95rem;
  color: var(--muted);
}

.nav-links a:hover {
  color: var(--text);
}

.menu-toggle {
  display: none;
  border: 1px solid var(--line);
  background: var(--card);
  border-radius: 10px;
  padding: 0.4rem 0.65rem;
  font-size: 1.1rem;
  cursor: pointer;
}

.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 5.5rem 1.5rem;
}

.alt-section {
  max-width: 100%;
  background: var(--bg-alt);
  padding-left: max(1.5rem, calc((100% - var(--max-width)) / 2 + 1.5rem));
  padding-right: max(1.5rem, calc((100% - var(--max-width)) / 2 + 1.5rem));
}

.hero {
  min-height: 88vh;
  display: flex;
  align-items: center;
}

.hero-content {
  width: 100%;
  display: grid;
  grid-template-columns: 1.4fr 0.8fr;
  gap: 4rem;
  align-items: center;
}

.eyebrow {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

h1 {
  font-size: clamp(2.7rem, 8vw, 5.7rem);
  line-height: 0.95;
  letter-spacing: -0.07em;
  margin-bottom: 1.25rem;
}

h2 {
  font-size: clamp(1.65rem, 3.4vw, 2.45rem);
  line-height: 1.12;
  letter-spacing: -0.055em;
  margin-bottom: 1.25rem;
}

h3 {
  font-size: 1.18rem;
  line-height: 1.25;
  letter-spacing: -0.025em;
  margin-bottom: 0.55rem;
}

.hero h2 {
  max-width: 800px;
  font-weight: 650;
}

.hero-description {
  color: var(--muted);
  max-width: 680px;
  font-size: 1.08rem;
}

.hero-image {
  display: flex;
  justify-content: center;
}

.hero-image img {
  width: min(310px, 80vw);
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border-radius: 50%;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  background: var(--bg-alt);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.button-row.small {
  margin-top: 1.2rem;
  gap: 0.55rem;
}

.button-row.center {
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--text);
  border-radius: 999px;
  padding: 0.72rem 1.05rem;
  font-size: 0.92rem;
  font-weight: 650;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  background: var(--accent-soft);
}

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

.btn.primary:hover {
  background: #000000;
}

.section-heading {
  max-width: 760px;
  margin-bottom: 2rem;
}

.center-heading {
  margin-left: auto;
  margin-right: auto;
}

.two-column {
  display: grid;
  grid-template-columns: 1.3fr 0.7fr;
  gap: 2rem;
  align-items: start;
}

.info-card,
.card,
.timeline-item,
.publication-item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.info-card ul {
  padding-left: 1.2rem;
  color: var(--muted);
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.2rem;
}

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

.compact-card p {
  margin-bottom: 0;
}

.card p,
.timeline-item p,
.publication-item p {
  color: var(--muted);
}

.muted {
  color: var(--muted);
  font-size: 0.95rem;
}

.timeline {
  display: grid;
  gap: 1.2rem;
}

.project-card {
  display: flex;
  flex-direction: column;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: auto;
  padding-top: 1rem;
}

.tag-row span {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.32rem 0.65rem;
  font-size: 0.8rem;
  color: var(--muted);
  background: var(--bg-alt);
}

.publication-list {
  display: grid;
  gap: 1.2rem;
}

.publication-type {
  margin-bottom: 0.35rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.contact-section {
  text-align: left;
  max-width: 900px;
}

.contact-content {
  max-width: 820px;
  margin-top: -0.3rem;
}

.contact-content p {
  margin: 0.25rem 0;
  line-height: 1.35;
}

.contact-name {
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.6rem !important;
}

.contact-icons {
  margin-top: 0.85rem;
  margin-bottom: 0.9rem;
  display: block;
  line-height: 1;
}

.contact-icons a {
  text-decoration: none;
  display: inline-block;
  vertical-align: middle;
}

.contact-icons img {
  height: 30px !important;
  width: auto !important;
  max-height: 30px;
  max-width: none;
  display: inline-block;
  vertical-align: middle;
  object-fit: contain;
}

.contact-logo {
  margin-top: 1.6rem;
  display: block;
}

.iele-logo {
  width: min(293px, 100%);
  height: auto;
  display: block;
}

.footer {
  border-top: 1px solid var(--line);
  padding: 2rem 1.5rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 900px) {
  .three-cards {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 820px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 68px;
    left: 1rem;
    right: 1rem;
    display: none;
    flex-direction: column;
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 1rem;
    box-shadow: var(--shadow);
  }

  .nav-links.open {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding-top: 4rem;
  }

  .hero-content,
  .two-column {
    grid-template-columns: 1fr;
  }

  .hero-image {
    order: -1;
  }

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

@media (max-width: 520px) {
  .iele-logo {
    width: min(286px, 100%);
  }

  .section {
    padding: 4rem 1rem;
  }

  .navbar {
    padding: 0.9rem 1rem;
  }

  .button-row {
    gap: 0.55rem;
  }

  .btn {
    width: 100%;
  }

  .button-row.small .btn {
    width: auto;
  }
}