:root {
  --navy: #0f172a;
  --navy-light: #1e293b;
  --accent: #3b82f6;
  --accent-dark: #2563eb;
  --text: #1e293b;
  --muted: #64748b;
  --border: #e2e8f0;
  --bg: #f8fafc;
  --card: #ffffff;
  --radius: 12px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

/* ── Navbar ── */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 60px;
}

.navbar__name {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  color: #e2e8f0;
  text-decoration: none;
  letter-spacing: -0.2px;
}
.navbar__name span { color: var(--accent); }

.navbar__links {
  display: flex;
  list-style: none;
  gap: 4px;
}

.navbar__links a {
  display: block;
  padding: 6px 14px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  color: #94a3b8;
  border-radius: 6px;
  transition: color 0.15s, background 0.15s;
}
.navbar__links a:hover { color: #e2e8f0; background: rgba(255,255,255,0.06); }

/* ── Page container ── */
.page {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 24px 80px;
}

/* ── Hero ── */
.hero {
  padding: 72px 0 56px;
  display: flex;
  align-items: center;
  gap: 48px;
}

.hero__photo {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--accent);
  flex-shrink: 0;
  box-shadow: 0 0 0 6px rgba(59,130,246,0.15);
}

.hero__text {}

.hero__greeting {
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.hero__name {
  font-size: 42px;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -1px;
  line-height: 1.1;
  margin-bottom: 12px;
}

.hero__tagline {
  font-size: 17px;
  color: var(--muted);
  max-width: 480px;
  line-height: 1.6;
  margin-bottom: 24px;
}

.hero__links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  background: var(--accent);
  color: white;
  border-radius: 8px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  transition: background 0.15s, transform 0.1s;
}
.btn-primary:hover { background: var(--accent-dark); transform: translateY(-1px); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  background: transparent;
  color: var(--text);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  transition: border-color 0.15s, background 0.15s;
}
.btn-secondary:hover { border-color: var(--accent); background: rgba(59,130,246,0.04); }

/* ── Section ── */
.section {
  padding: 48px 0;
  border-top: 1px solid var(--border);
}

.section__label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}

.section__title {
  font-size: 28px;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.5px;
  margin-bottom: 20px;
}

.section__body {
  font-size: 16px;
  color: var(--muted);
  line-height: 1.75;
  max-width: 680px;
}
.section__body p + p { margin-top: 14px; }

/* ── Research eras ── */
.research-era {
  margin-bottom: 36px;
}

.research-era__header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.research-era__badge {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--accent);
  color: white;
  flex-shrink: 0;
}

.research-era__badge--secondary {
  background: transparent;
  color: var(--muted);
  border: 1.5px solid var(--border);
}

.research-era__school {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}

/* ── Research cards ── */
.research-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 24px;
}

.research-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.research-card__icon {
  font-size: 24px;
  margin-bottom: 10px;
}

.research-card__title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}

.research-card__desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
}

/* ── CV embed ── */
.cv-toggle {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.cv-toggle__btn {
  padding: 8px 20px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}

.cv-toggle__btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.cv-toggle__btn--active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.cv-wrapper {
  margin-top: 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--card);
}

.cv-stack {
  position: relative;
  height: 900px;
}

.cv-pane {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  pointer-events: none;
  display: block;
}

.cv-pane--active {
  opacity: 1;
  pointer-events: auto;
}

.cv-download {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 12px;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
}
.cv-download:hover { text-decoration: underline; }

/* ── Project cards ── */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 24px;
}

.project-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  text-decoration: none;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.1s;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}
.project-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(59,130,246,0.12);
  transform: translateY(-2px);
}

.project-card__emoji { font-size: 28px; margin-bottom: 12px; }

.project-card__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}

.project-card__desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.55;
}

.project-card__status {
  display: inline-block;
  margin-top: 12px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent);
  background: rgba(59,130,246,0.08);
  padding: 3px 8px;
  border-radius: 4px;
}

/* ── Footer ── */
.footer {
  text-align: center;
  padding: 32px 24px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--muted);
}

/* ── Responsive ── */
@media (max-width: 640px) {
  .navbar { padding: 0 16px; }
  .page { padding: 0 16px 60px; }
  .hero { flex-direction: column; gap: 24px; padding: 48px 0 36px; text-align: center; }
  .hero__links { justify-content: center; }
  .hero__name { font-size: 32px; }
  .hero__photo { width: 110px; height: 110px; }
  .research-grid, .projects-grid { grid-template-columns: 1fr; }
  .navbar__links { display: none; }
}