/* ============================================
   Design tokens
   ============================================ */
:root {
  --bg: #0a0e14;
  --bg-alt: #0d1219;
  --surface: #10161f;
  --surface-hover: #141c27;
  --border: #1f2937;
  --border-light: #2a3544;
  --text: #e4e9f0;
  --text-dim: #8b95a5;
  --text-faint: #5a6478;
  --accent: #5eead4;
  --accent-dim: #2dd4bf;
  --accent-glow: rgba(94, 234, 212, 0.15);
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --max-width: 1100px;
  --transition: 200ms ease;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

ul { list-style: none; }

img { max-width: 100%; display: block; }

::selection { background: var(--accent-glow); color: var(--accent); }

.accent { color: var(--accent); }

.noise-overlay {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1000;
  opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ============================================
   Header / Nav
   ============================================ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 14, 20, 0.75);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.navbar {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-link {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dim);
  transition: color var(--transition);
  position: relative;
}

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

.nav-link::before { content: "."; opacity: 0; margin-right: 2px; }

.nav-link.active { color: var(--accent); }

.nav-cta {
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--border-light);
  border-radius: 4px;
  color: var(--text) !important;
}

.nav-cta:hover {
  border-color: var(--accent);
  color: var(--accent) !important;
  background: var(--accent-glow);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================
   Hero
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 6rem 1.5rem 2rem;
  position: relative;
  background:
    radial-gradient(ellipse 60% 50% at 50% 0%, var(--accent-glow), transparent 70%),
    var(--bg);
}

.hero-inner {
  max-width: 780px;
  text-align: center;
}

.hero-inner-split {
  max-width: 1000px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3.5rem;
  text-align: left;
}

.hero-text { flex: 1 1 480px; max-width: 560px; }

.hero-inner-split .hero-subtitle { margin: 0 0 2rem; }
.hero-inner-split .hero-actions { justify-content: flex-start; margin-bottom: 2.25rem; }

.hero-photo-wrap {
  position: relative;
  flex: 0 0 auto;
  width: 260px;
  height: 260px;
}

.hero-photo-glow {
  position: absolute;
  inset: -18px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-glow), transparent 70%);
  filter: blur(6px);
}

.hero-photo {
  position: relative;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--border-light);
  box-shadow: 0 0 0 6px var(--bg), 0 12px 40px rgba(0, 0, 0, 0.45);
}

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1.75rem;
}

.hero-stat {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.hero-stat-num {
  font-family: var(--font-mono);
  color: var(--accent);
  font-weight: 700;
  font-size: 1.2rem;
}

.hero-stat-label {
  font-size: 0.72rem;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.hero-eyebrow {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
}

.hero-title {
  font-size: clamp(2.2rem, 6vw, 3.6rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1.5rem;
}

.hero-subtitle {
  color: var(--text-dim);
  font-size: 1.1rem;
  max-width: 560px;
  margin: 0 auto 2.25rem;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.btn {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  padding: 0.8rem 1.6rem;
  border-radius: 6px;
  transition: all var(--transition);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: #061410;
  font-weight: 600;
}

.btn-primary:hover {
  background: var(--accent-dim);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--accent-glow);
}

.btn-ghost {
  border-color: var(--border-light);
  color: var(--text);
}

.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.hero-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-dim);
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 0 var(--accent-glow);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(94, 234, 212, 0.5); }
  70% { box-shadow: 0 0 0 8px rgba(94, 234, 212, 0); }
  100% { box-shadow: 0 0 0 0 rgba(94, 234, 212, 0); }
}

.hero-scroll-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-faint);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.scroll-line {
  width: 1px;
  height: 32px;
  background: linear-gradient(var(--text-faint), transparent);
  animation: scrollLine 2s ease infinite;
}

@keyframes scrollLine {
  0% { opacity: 0; transform: scaleY(0); transform-origin: top; }
  50% { opacity: 1; transform: scaleY(1); transform-origin: top; }
  100% { opacity: 0; transform: scaleY(1); transform-origin: bottom; }
}

/* ============================================
   Sections
   ============================================ */
.section {
  padding: 6rem 1.5rem;
}

.section-alt {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-tag {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 0.85rem;
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 2.5rem;
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 600ms ease, transform 600ms ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   About
   ============================================ */
.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 3rem;
  align-items: start;
}

.about-text {
  color: var(--text-dim);
  font-size: 1.05rem;
}

.about-facts {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  border-left: 2px solid var(--border-light);
  padding-left: 1.25rem;
}

.about-facts li {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.fact-label {
  color: var(--text-faint);
}

/* ============================================
   Section lead text
   ============================================ */
.section-lead {
  color: var(--text-dim);
  font-size: 1.02rem;
  max-width: 640px;
  margin: -1.25rem 0 2.5rem;
}

.section-lead-small {
  color: var(--text-dim);
  font-size: 0.92rem;
  margin: -0.5rem 0 1rem;
}

.subgroup-heading {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--text);
  margin: 2.5rem 0 1.25rem;
}

.subgroup-heading:first-of-type { margin-top: 0; }

/* ============================================
   Education & certifications
   ============================================ */
.edu-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 3rem;
  align-items: start;
}

.edu-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.edu-list h3 {
  font-size: 1.02rem;
  margin-bottom: 0.3rem;
}

.edu-org {
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.cert-heading {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: var(--text);
}

/* ============================================
   Teaching / faculty grid
   ============================================ */
.faculty-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.faculty-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.1rem 1rem;
  font-size: 0.9rem;
  text-align: center;
  transition: border-color var(--transition), transform var(--transition);
}

.faculty-card:hover {
  border-color: var(--accent-dim);
  transform: translateY(-3px);
}

.faculty-card-more {
  color: var(--text-faint);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  border-style: dashed;
}

/* ============================================
   Achievements
   ============================================ */
.achv-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-bottom: 1rem;
}

.achv-card {
  display: flex;
  gap: 0.9rem;
  align-items: flex-start;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem 1.4rem;
}

.achv-icon {
  color: var(--accent);
  font-size: 1rem;
  line-height: 1.5;
  flex-shrink: 0;
}

.achv-card p {
  color: var(--text-dim);
  font-size: 0.92rem;
  line-height: 1.55;
}

.achv-card strong { color: var(--text); }

.tag-list-achv .tag {
  color: var(--text-dim);
  background: var(--surface);
  border-color: var(--border-light);
}

/* ============================================
   Testimonials
   ============================================ */
.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.testimonial-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.5rem;
  margin: 0;
  transition: border-color var(--transition), transform var(--transition);
}

.testimonial-card:hover {
  border-color: var(--accent-dim);
  transform: translateY(-3px);
}

.testimonial-card p {
  font-size: 0.94rem;
  color: var(--text-dim);
  line-height: 1.6;
  margin-bottom: 1rem;
}

.testimonial-card cite {
  font-family: var(--font-mono);
  font-style: normal;
  font-size: 0.82rem;
  color: var(--accent);
}

.testimonial-card cite span {
  color: var(--text-faint);
}

.contact-phone {
  font-family: var(--font-mono);
  color: var(--text-dim);
  font-size: 0.95rem;
  margin-top: 0.5rem;
}

/* ============================================
   Skills
   ============================================ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.skill-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.75rem;
  transition: border-color var(--transition), transform var(--transition);
}

.skill-card:hover {
  border-color: var(--border-light);
  transform: translateY(-3px);
}

.skill-card h3 {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: var(--text);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  background: var(--accent-glow);
  padding: 0.3rem 0.65rem;
  border-radius: 4px;
  border: 1px solid rgba(94, 234, 212, 0.2);
}

/* ============================================
   Projects
   ============================================ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.75rem;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.project-card:hover {
  border-color: var(--accent-dim);
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
}

.project-card-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.project-index {
  font-family: var(--font-mono);
  color: var(--text-faint);
  font-size: 0.85rem;
}

.project-links {
  display: flex;
  gap: 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.project-links a {
  color: var(--text-dim);
  transition: color var(--transition);
}

.project-links a:hover { color: var(--accent); }

.project-title {
  font-size: 1.15rem;
  margin-bottom: 0.6rem;
}

.project-desc {
  color: var(--text-dim);
  font-size: 0.92rem;
  margin-bottom: 1.25rem;
}

/* ============================================
   Experience / timeline
   ============================================ */
.timeline {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.timeline-item {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 2rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--border);
}

.timeline-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.timeline-date {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 0.85rem;
}

.timeline-content h3 {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.timeline-org {
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  margin-bottom: 0.6rem;
}

.timeline-desc {
  color: var(--text-dim);
  font-size: 0.95rem;
}

/* ============================================
   Contact
   ============================================ */
.contact-section {
  text-align: center;
}

.contact-text {
  color: var(--text-dim);
  max-width: 480px;
  margin: 0 auto 1.75rem;
}

.contact-email {
  font-family: var(--font-mono);
  font-size: clamp(1.3rem, 4vw, 1.8rem);
  color: var(--accent);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}

.contact-email:hover {
  border-color: var(--accent);
}

.social-links {
  display: flex;
  gap: 1.75rem;
  justify-content: center;
  margin-top: 2.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.social-links a {
  color: var(--text-dim);
  transition: color var(--transition);
}

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

/* ============================================
   Footer
   ============================================ */
.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 3rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-faint);
}

.back-to-top {
  color: var(--text-faint);
  transition: color var(--transition);
}

.back-to-top:hover { color: var(--accent); }

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 860px) {
  .about-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: 1fr 1fr; }
  .projects-grid { grid-template-columns: 1fr; }
  .timeline-item { grid-template-columns: 1fr; gap: 0.5rem; }
  .hero-inner-split { flex-direction: column-reverse; text-align: center; gap: 2rem; }
  .hero-text { max-width: 100%; }
  .hero-inner-split .hero-actions,
  .hero-stats { justify-content: center; }
  .hero-photo-wrap { width: 190px; height: 190px; }
  .edu-grid { grid-template-columns: 1fr; }
  .faculty-grid { grid-template-columns: repeat(2, 1fr); }
  .achv-grid { grid-template-columns: 1fr; }
  .testimonial-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 300ms ease;
  }

  .nav-links.open { max-height: 320px; }

  .nav-links li { width: 100%; }

  .nav-link {
    display: block;
    padding: 1rem 1.5rem;
    width: 100%;
    border-bottom: 1px solid var(--border);
  }

  .skills-grid { grid-template-columns: 1fr; }
  .faculty-grid { grid-template-columns: 1fr 1fr; }
  .testimonial-grid { grid-template-columns: 1fr; }

  .site-footer { flex-direction: column; gap: 0.75rem; text-align: center; }
}