/* ---------- RESET & GLOBAL ---------- */
:root {
  --primary: #1e90ff;
  --overlay: rgba(0, 0, 0, 0.65);
  --text-muted: #cbd5e1;
  --maxw: 1200px;
}

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

html, body {
  height: 100%;
  font-family: 'Inter', Arial, sans-serif;
  color: #f5f7fa;
  scroll-behavior: smooth;
}

/* Star background with dark overlay */
body {
  background: url('sky3.png') center / cover fixed no-repeat;
}
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: var(--overlay);
  z-index: -1;
}

/* ---------- NAVBAR ---------- */
header {
  position: sticky;
  top: 0;
  backdrop-filter: blur(10px);
  background: rgba(0, 0, 0, 0.55);
}
.navbar {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo { font-size: 1.25rem; font-weight: 700; color: #f5f7fa; }
.navbar ul { list-style: none; display: flex; gap: 1.5rem; }
.navbar a { text-decoration: none; color: inherit; }
.navbar a:hover { color: var(--primary); }

/* ---------- MAIN LAYOUT ---------- */
main { max-width: var(--maxw); width: 90%; margin: 0 auto; padding: 4rem 0; }
section { margin-bottom: 4rem; }

/* ---------- HERO ---------- */
.hero { display: flex; flex-direction: column; align-items: center; text-align: center; gap: 1.5rem; }
.hero img {
  width: 200px; height: 200px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}
.hero h1 { font-size: 2.5rem; }
.hero h2 { font-size: 1.25rem; font-weight: 400; color: var(--text-muted); line-height: 1.4; }
.hero p { max-width: 700px; line-height: 1.6; }

/* ---------- SECTION HEADERS ---------- */
section h3 {
  font-size: 1.75rem;
  border-bottom: 2px solid var(--primary);
  display: inline-block;
  margin-bottom: 1rem;
}

/* ---------- PUBLICATIONS ---------- */
.pub-list { display: grid; gap: 1rem; list-style: none; }
.pub-list a { color: var(--primary); text-decoration: none; }
.pub-list a:hover { text-decoration: underline; }

/* ---------- CONTACT ---------- */
address { text-align: center; line-height: 1.8; }

/* ---------- LINKS ---------- */
.social { display: flex; gap: 1rem; flex-wrap: wrap; justify-content: center; }
.social a { color: #f5f7fa; }
.social a:hover { color: var(--primary); }

/* ---------- FOOTER ---------- */
footer { text-align: center; padding: 2rem 0; font-size: 0.875rem; color: var(--text-muted); }

/* ---------- RESPONSIVE ---------- */
@media (min-width: 768px) {
  .hero { flex-direction: row; text-align: left; }
  .hero img { margin-right: 2rem; }
}