/* === RESET & BASE === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  /* Dark mode palette */
  --bg:        #09090f;
  --bg-alt:    #0d0d16;
  --surface:   #12121c;
  --border:    #1c1c2b;
  --border-hl: #2c2c44;
  --text:      #e6eaf2;
  --text-mid:  #7a8599;
  --text-dim:  #3a4255;
  --accent:    #4d9cff;
  --accent-dk: #2563eb;
  --accent-lt: #091525;
  --glow:      rgba(77,156,255,.14);
  --glow-str:  rgba(77,156,255,.28);

  --radius: 12px;
  --trans:  .22s ease;
  --font:   'Inter', system-ui, -apple-system, sans-serif;
}

html { scroll-behavior: smooth; }

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

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
strong { color: var(--text); }

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== NAVBAR ===== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(9,9,15,.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--trans), box-shadow var(--trans);
}
.navbar.scrolled {
  border-color: var(--border);
  box-shadow: 0 1px 24px rgba(0,0,0,.5);
}
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
}
.nav-brand {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.02em;
  white-space: nowrap;
  margin-right: auto;
}
.nav-links {
  display: flex;
  gap: 28px;
  margin-right: 20px;
}
.nav-links a {
  font-size: .875rem;
  font-weight: 500;
  color: var(--text-mid);
  transition: color var(--trans);
}
.nav-links a:hover { color: var(--accent); }

.nav-icons {
  display: flex;
  gap: 2px;
  align-items: center;
}
.icon-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: 8px;
  color: var(--text-mid);
  transition: color var(--trans), background var(--trans);
}
.icon-link:hover { color: var(--accent); background: var(--accent-lt); }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  margin-left: 8px;
}
.hamburger span {
  width: 22px; height: 2px;
  background: var(--text);
  display: block;
  border-radius: 2px;
  transition: transform var(--trans), opacity var(--trans);
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== HERO ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: 64px;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 55% at 40% -5%, rgba(77,156,255,.1) 0%, transparent 65%);
  pointer-events: none;
}
.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(77,156,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(77,156,255,.035) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 70% 70% at 40% 50%, black 5%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 70% 70% at 40% 50%, black 5%, transparent 75%);
}
.hero-layout {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 64px;
  align-items: center;
  position: relative;
  z-index: 1;
  padding: 80px 24px;
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
}
.hero-text { max-width: 600px; }

.hero-greeting {
  font-size: .95rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 10px;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.hero-name {
  font-size: clamp(3rem, 7.5vw, 5.5rem);
  font-weight: 800;
  color: var(--text);
  line-height: 1.05;
  letter-spacing: -.04em;
  margin-bottom: 14px;
}
.hero-title {
  font-size: clamp(1rem, 2.2vw, 1.3rem);
  font-weight: 500;
  color: var(--text-mid);
  margin-bottom: 20px;
}
.hero-desc {
  font-size: 1rem;
  color: var(--text-mid);
  max-width: 520px;
  line-height: 1.78;
  margin-bottom: 36px;
}
.hero-btns {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}
.hero-tags {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  font-size: .8rem;
  color: var(--text-dim);
  font-weight: 500;
}
.hero-tags span { white-space: nowrap; }

/* Profile photo */
.hero-photo { flex-shrink: 0; }
.photo-frame {
  width: 280px;
  height: 280px;
  border-radius: 50%;
  overflow: hidden;
  border: 2px solid var(--border-hl);
  box-shadow: 0 0 0 6px var(--accent-lt), 0 0 48px var(--glow);
  position: relative;
}
.photo-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  display: block;
}
.photo-frame::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: linear-gradient(to bottom, transparent 60%, rgba(9,9,15,.3) 100%);
}

.hero-scroll-hint {
  position: absolute;
  bottom: 36px;
  left: 50%;
  transform: translateX(-50%);
}
.scroll-line {
  width: 1px;
  height: 52px;
  background: linear-gradient(to bottom, transparent, var(--border));
  margin: 0 auto;
  animation: pulse-line 2.2s ease-in-out infinite;
}
@keyframes pulse-line {
  0%, 100% { opacity: 0; transform: scaleY(.5); transform-origin: top; }
  50%       { opacity: 1; transform: scaleY(1); }
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: 8px;
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans);
  border: 1.5px solid transparent;
  white-space: nowrap;
  font-family: var(--font);
}
.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.btn-primary:hover {
  background: #6aadff;
  border-color: #6aadff;
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(77,156,255,.4);
}
.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border-hl);
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
  background: var(--accent-lt);
}

/* ===== SECTIONS ===== */
.section     { padding: 100px 0; }
.section-alt { background: var(--bg-alt); }

.section-header { margin-bottom: 52px; }
.section-header h2 {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.03em;
  margin-bottom: 10px;
}
.section-line {
  width: 44px; height: 3px;
  background: var(--accent);
  border-radius: 3px;
  margin-bottom: 10px;
  box-shadow: 0 0 12px var(--glow);
}
.section-sub {
  color: var(--text-mid);
  font-size: 1rem;
  margin-top: 6px;
}

/* ===== ABOUT ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}
.about-bio p {
  color: var(--text-mid);
  margin-bottom: 16px;
  line-height: 1.8;
}
.edu-block {
  display: flex;
  gap: 16px;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-top: 24px;
}
.edu-logo {
  font-size: .72rem;
  font-weight: 800;
  color: var(--accent);
  background: var(--accent-lt);
  border: 1.5px solid rgba(77,156,255,.25);
  border-radius: 8px;
  padding: 8px 10px;
  min-width: 60px;
  text-align: center;
  letter-spacing: .06em;
  flex-shrink: 0;
}
.edu-info {
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.edu-info strong { color: var(--text);     font-size: .95rem; }
.edu-info span   { color: var(--text-mid); font-size: .83rem; }

.skills-grid {
  display: flex;
  flex-direction: column;
  gap: 24px;
}
.skill-group h4 {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .1em;
  color: var(--text-dim);
  margin-bottom: 10px;
}
.tag-list { display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: .78rem;
  font-weight: 500;
  background: var(--surface);
  color: var(--text-mid);
  border: 1px solid var(--border);
}

/* ===== PROJECTS ===== */

/* ---- Main featured (Drone Mapper) ---- */
.project-featured {
  margin-bottom: 20px;
  padding: 36px 40px !important;
  border-color: rgba(77,156,255,.2) !important;
  background: linear-gradient(135deg, var(--surface) 55%, #0d1525) !important;
}
.project-featured:hover {
  border-color: rgba(77,156,255,.4) !important;
  box-shadow: 0 0 0 1px rgba(77,156,255,.15), 0 12px 40px rgba(77,156,255,.12) !important;
}
.featured-body {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 40px;
  align-items: stretch;
}
.featured-top {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 16px;
}
.featured-badge {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .1em;
  color: var(--accent);
  background: var(--accent-lt);
  border: 1px solid rgba(77,156,255,.2);
  border-radius: 20px;
  padding: 4px 12px;
}
.featured-left h3 {
  font-size: 1.5rem !important;
  color: var(--text) !important;
  margin-bottom: 14px;
}
.featured-left p {
  font-size: .91rem;
  color: var(--text-mid);
  line-height: 1.76;
  margin-bottom: 12px;
}
.featured-right {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.featured-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  flex: 1;
}
.stat {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 10px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  text-align: center;
}
.stat-num {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -.02em;
  line-height: 1;
}
.stat-label {
  font-size: .66rem;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: .06em;
}

/* ---- Secondary featured (ASL with video) ---- */
.project-secondary {
  margin-bottom: 20px;
  padding: 28px 32px !important;
}
.secondary-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
}
.secondary-badge-row {
  display: flex;
  gap: 8px;
  margin: 8px 0 12px;
}
.secondary-badge {
  font-size: .68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--text-mid);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 3px 10px;
}
.secondary-left h3 {
  font-size: 1.15rem !important;
  color: var(--text) !important;
  margin-bottom: 6px;
}
.secondary-left p {
  font-size: .88rem;
  color: var(--text-mid);
  line-height: 1.7;
  margin-bottom: 14px;
}
.video-label {
  font-size: .72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--text-dim);
  margin-bottom: 10px;
}
.video-thumb {
  display: block;
  position: relative;
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--border);
  transition: border-color var(--trans), box-shadow var(--trans);
}
.video-thumb:hover {
  border-color: rgba(77,156,255,.4);
  box-shadow: 0 0 24px var(--glow);
}
.video-thumb img {
  width: 100%;
  display: block;
  aspect-ratio: 16/9;
  object-fit: cover;
}
.video-play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,.35);
  transition: background var(--trans);
}
.video-thumb:hover .video-play { background: rgba(0,0,0,.15); }
.video-play svg { filter: drop-shadow(0 2px 8px rgba(0,0,0,.5)); transition: transform var(--trans); }
.video-thumb:hover .video-play svg { transform: scale(1.1); }

/* ---- Regular grid ---- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: transform var(--trans), box-shadow var(--trans), border-color var(--trans);
  overflow: hidden;
}
.project-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 0 0 1px rgba(77,156,255,.15), 0 8px 32px rgba(77,156,255,.1);
  border-color: var(--border-hl);
}

/* Card photo at top */
.card-img-wrap {
  margin: -24px -24px 16px;
  height: 180px;
  overflow: hidden;
}
.card-img-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
  transition: transform .4s ease;
}
.project-card:hover .card-img-wrap img { transform: scale(1.04); }

.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}
.card-icon { font-size: 1.8rem; line-height: 1; }

.card-links { display: flex; gap: 8px; }
.card-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px; height: 32px;
  border-radius: 6px;
  color: var(--text-dim);
  border: 1px solid var(--border);
  background: var(--bg);
  transition: all var(--trans);
}
.card-links a:hover {
  color: var(--accent);
  border-color: rgba(77,156,255,.4);
  background: var(--accent-lt);
  box-shadow: 0 0 8px var(--glow);
}

.project-card h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.01em;
}
.project-card p {
  font-size: .86rem;
  color: var(--text-mid);
  line-height: 1.65;
  flex: 1;
}
.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 4px;
}

/* Tag colors (dark-mode friendly) */
.tag-cpp    { background:#1f1500; color:#f59e0b; border-color:#3a2800; }
.tag-python { background:#001f0f; color:#34d399; border-color:#00361a; }
.tag-java   { background:#1f0900; color:#fb923c; border-color:#3a1500; }
.tag-js     { background:#1f1a00; color:#fbbf24; border-color:#3a3000; }
.tag-ts     { background:#001228; color:#60a5fa; border-color:#00214a; }
.tag-robot  { background:#001a0f; color:#4ade80; border-color:#003019; }
.tag-ai     { background:#170028; color:#c084fc; border-color:#2d0052; }
.tag-algo   { background:#091525; color:#4d9cff; border-color:#102340; }
.tag-hw     { background:#001824; color:#38bdf8; border-color:#002d44; }
.tag-db     { background:#141210; color:#a8a29e; border-color:#28241f; }
.tag-sw     { background:#111111; color:#d4d4d4; border-color:#222222; }
.tag-web    { background:#00150e; color:#34d399; border-color:#00261a; }

/* ===== RESEARCH ===== */
.research-card {
  display: flex;
  gap: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px;
  align-items: flex-start;
  transition: border-color var(--trans), box-shadow var(--trans);
}
.research-card:hover {
  border-color: var(--border-hl);
  box-shadow: 0 0 0 1px rgba(77,156,255,.1), 0 8px 32px rgba(77,156,255,.07);
}
.research-icon-wrap {
  flex-shrink: 0;
  width: 64px; height: 64px;
  background: var(--accent-lt);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  border: 1px solid rgba(77,156,255,.2);
}
.research-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 4px;
}
.research-meta h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
}
.badge {
  display: inline-flex;
  padding: 3px 10px;
  background: var(--accent-lt);
  color: var(--accent);
  border-radius: 20px;
  font-size: .73rem;
  font-weight: 600;
  border: 1px solid rgba(77,156,255,.2);
}
.research-role  { color: var(--text-mid); font-size: .88rem; margin-bottom: 12px; }
.research-body p { color: var(--text-mid); line-height: 1.75; margin-bottom: 16px; }

/* ===== TIMELINE ===== */
.timeline { position: relative; display: flex; flex-direction: column; }
.timeline::before {
  content: '';
  position: absolute;
  left: 8px; top: 8px; bottom: 8px;
  width: 2px;
  background: var(--border);
  border-radius: 2px;
}
.tl-item {
  display: flex;
  gap: 32px;
  padding-bottom: 48px;
  position: relative;
}
.tl-item:last-child { padding-bottom: 0; }
.tl-marker {
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--bg);
  border: 2.5px solid var(--accent);
  flex-shrink: 0;
  margin-top: 3px;
  position: relative;
  z-index: 1;
  transition: background var(--trans), box-shadow var(--trans);
}
.tl-item:hover .tl-marker {
  background: var(--accent-lt);
  box-shadow: 0 0 12px var(--glow);
}
.tl-content { flex: 1; }
.tl-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 12px;
}
.tl-head h3    { font-size: 1.02rem; font-weight: 700; color: var(--text); margin-bottom: 2px; }
.tl-org        { display: block; font-size: .83rem; color: var(--accent); font-weight: 600; }
.tl-date       { font-size: .8rem;  color: var(--text-dim); white-space: nowrap; font-weight: 500; padding-top: 2px; }
.tl-content ul { list-style: disc; padding-left: 20px; display: flex; flex-direction: column; gap: 8px; }
.tl-content li { font-size: .88rem; color: var(--text-mid); line-height: 1.65; }

.tl-social {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 14px;
  font-size: .82rem;
  font-weight: 600;
  color: var(--text-mid);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 14px;
  background: var(--bg-alt);
  transition: all var(--trans);
}
.tl-social:hover {
  color: var(--accent);
  border-color: rgba(77,156,255,.3);
  background: var(--accent-lt);
}

/* ===== CONTACT ===== */
.contact-wrap { text-align: center; }
.contact-wrap .section-header { display: flex; flex-direction: column; align-items: center; }
.contact-wrap .section-line   { margin: 0 auto 10px; }
.contact-intro {
  color: var(--text-mid);
  font-size: 1.05rem;
  max-width: 480px;
  margin: 0 auto 40px;
  line-height: 1.75;
}
.contact-btns { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* ===== FOOTER ===== */
.footer { background: #06060d; border-top: 1px solid var(--border); padding: 36px 0; }
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-brand { font-weight: 700; color: var(--text); font-size: .95rem; }
.footer-links { display: flex; gap: 20px; align-items: center; }
.footer-links a {
  font-size: .84rem;
  color: var(--text-dim);
  transition: color var(--trans);
}
.footer-links a:hover { color: var(--accent); }
.footer-copy { font-size: .8rem; color: var(--text-dim); }

/* ===== FADE-UP ===== */
.fade-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .55s ease, transform .55s ease;
}
.fade-up.visible { opacity: 1; transform: translateY(0); }

/* ===== RESPONSIVE ===== */
@media (max-width: 1000px) {
  .projects-grid { grid-template-columns: repeat(2, 1fr); }
  .about-grid    { grid-template-columns: 1fr; gap: 48px; }
  .featured-body { grid-template-columns: 1fr; }
  .featured-right { flex-direction: row; align-items: center; }
  .featured-stats { flex: 1; }
  .hero-layout { grid-template-columns: 1fr; }
  .hero-photo  { display: none; }
}
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: fixed;
    top: 64px; left: 0; right: 0;
    background: rgba(9,9,15,.97);
    border-bottom: 1px solid var(--border);
    padding: 20px 24px;
    flex-direction: column;
    gap: 18px;
    z-index: 99;
    box-shadow: 0 12px 40px rgba(0,0,0,.6);
  }
  .nav-links.open { display: flex; }
  .nav-icons      { display: none; }
  .hamburger      { display: flex; }
  .section        { padding: 72px 0; }
  .tl-head        { flex-direction: column; gap: 4px; }
  .research-card  { flex-direction: column; gap: 20px; padding: 24px; }
  .secondary-body { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .projects-grid  { grid-template-columns: 1fr; }
  .hero-btns      { flex-direction: column; align-items: flex-start; }
  .contact-btns   { flex-direction: column; align-items: center; }
  .footer-inner   { flex-direction: column; text-align: center; }
  .project-featured { padding: 24px !important; }
  .featured-body  { gap: 24px; }
  .featured-right { flex-direction: column; }
}