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

:root{
  --color-bg:#0a0a0b;
  --color-bg-alt:#0f0f11;
  --color-bg-card:#141416;
  --color-bg-card-hover:#1a1a1e;
  --color-primary:#6366f1;
  --color-primary-light:#818cf8;
  --color-primary-dim:rgba(99,102,241,0.15);
  --color-primary-border:rgba(99,102,241,0.25);
  --color-text:#fafafa;
  --color-text-muted:#a1a1aa;
  --color-text-subtle:#71717a;
  --color-border:rgba(255,255,255,0.07);
  --color-border-strong:rgba(255,255,255,0.12);
  --font-sans:Inter,-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;
  --radius-sm:4px;
  --radius-md:8px;
  --radius-lg:12px;
  --radius-xl:16px;
  --radius-full:9999px;
  --shadow-sm:0 1px 3px rgba(0,0,0,0.3);
  --shadow-md:0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg:0 8px 32px rgba(0,0,0,0.5);
  --shadow-glow:0 0 40px rgba(99,102,241,0.15);
  --ease:cubic-bezier(0.4,0,0.2,1);
  --max-w:1280px;
}

html{scroll-behavior:smooth;font-size:16px}

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

/* SKIP LINK */
.skip-link{
  position:absolute;
  top:-100%;
  left:16px;
  z-index:9999;
  background:var(--color-primary);
  color:#fff;
  padding:8px 16px;
  border-radius:var(--radius-md);
  font-size:14px;
  font-weight:600;
  text-decoration:none;
  transition:top 200ms var(--ease);
}
.skip-link:focus{top:16px}

/* SCROLLBAR */
::-webkit-scrollbar{width:6px}
::-webkit-scrollbar-track{background:var(--color-bg)}
::-webkit-scrollbar-thumb{background:rgba(99,102,241,0.4);border-radius:3px}
::-webkit-scrollbar-thumb:hover{background:rgba(99,102,241,0.7)}

/* TYPOGRAPHY SCALE */
h1{font-size:clamp(40px,6vw,64px);font-weight:800;line-height:1.1;letter-spacing:-0.03em}
h2{font-size:clamp(28px,4vw,48px);font-weight:700;line-height:1.15;letter-spacing:-0.02em}
h3{font-size:clamp(20px,2.5vw,28px);font-weight:600;line-height:1.25;letter-spacing:-0.01em}
h4{font-size:clamp(15px,1.8vw,18px);font-weight:600;line-height:1.35}
p{line-height:1.65;color:var(--color-text-muted)}
strong{color:var(--color-text);font-weight:600}

a{color:inherit;text-decoration:none}
a:focus-visible{outline:2px solid var(--color-primary);outline-offset:3px;border-radius:var(--radius-sm)}

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

/* CONTAINER */
.container{
  width:100%;
  max-width:var(--max-w);
  margin:0 auto;
  padding:0 24px;
}

/* SECTION SPACING */
section{padding:96px 0}
@media(max-width:767px){section{padding:64px 0}}

/* SECTION LABELS */
.section-label{
  display:inline-block;
  font-size:11px;
  font-weight:700;
  letter-spacing:0.12em;
  text-transform:uppercase;
  color:var(--color-primary);
  background:var(--color-primary-dim);
  border:1px solid var(--color-primary-border);
  padding:4px 12px;
  border-radius:var(--radius-full);
  margin-bottom:16px;
}

.section-title{color:var(--color-text);margin-bottom:16px}
.section-subtitle{font-size:18px;color:var(--color-text-muted);margin-bottom:48px;max-width:600px}

/* DIVIDER */
.section-divider{
  width:100%;
  height:1px;
  background:var(--color-border);
}

/* ═══════════════════════
   HEADER / NAV
═══════════════════════ */
#navbar{
  position:fixed;
  top:0;
  left:0;
  right:0;
  z-index:1000;
  height:64px;
  display:flex;
  align-items:center;
  background:rgba(10,10,11,0.8);
  backdrop-filter:blur(16px);
  -webkit-backdrop-filter:blur(16px);
  border-bottom:1px solid transparent;
  transition:border-color 200ms var(--ease),box-shadow 200ms var(--ease);
}
#navbar.scrolled{
  border-bottom-color:var(--color-border);
  box-shadow:0 1px 24px rgba(0,0,0,0.4);
}

.nav-inner{
  width:100%;
  max-width:var(--max-w);
  margin:0 auto;
  padding:0 24px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
}

.nav-logo{
  font-size:16px;
  font-weight:700;
  color:var(--color-text);
  letter-spacing:-0.01em;
  white-space:nowrap;
  flex-shrink:0;
}
.nav-logo:hover{color:var(--color-primary-light)}

.nav-links{
  display:flex;
  align-items:center;
  gap:4px;
  list-style:none;
}

.nav-links a{
  font-size:14px;
  font-weight:500;
  color:var(--color-text-muted);
  padding:6px 12px;
  border-radius:var(--radius-md);
  transition:color 150ms var(--ease),background 150ms var(--ease);
}
.nav-links a:hover{color:var(--color-text);background:rgba(255,255,255,0.06)}

.nav-cta{
  flex-shrink:0;
}

.nav-cta a{
  display:inline-flex;
  align-items:center;
  gap:6px;
  font-size:14px;
  font-weight:600;
  color:#fff;
  background:var(--color-primary);
  padding:8px 18px;
  border-radius:var(--radius-md);
  transition:background 150ms var(--ease),transform 150ms var(--ease),box-shadow 150ms var(--ease);
}
.nav-cta a:hover{
  background:var(--color-primary-light);
  transform:translateY(-1px);
  box-shadow:0 4px 16px rgba(99,102,241,0.35);
}

/* HAMBURGER */
.hamburger{
  display:none;
  flex-direction:column;
  justify-content:center;
  align-items:center;
  gap:5px;
  width:40px;
  height:40px;
  background:none;
  border:1px solid var(--color-border-strong);
  border-radius:var(--radius-md);
  cursor:pointer;
  padding:0;
}
.hamburger span{
  display:block;
  width:18px;
  height:2px;
  background:var(--color-text);
  border-radius:1px;
  transition:transform 250ms var(--ease),opacity 250ms var(--ease);
}
.hamburger.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.hamburger.open span:nth-child(2){opacity:0;transform:scaleX(0)}
.hamburger.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

@media(max-width:767px){
  .hamburger{display:flex}
  .nav-links{
    display:none;
    position:absolute;
    top:64px;
    left:0;
    right:0;
    flex-direction:column;
    align-items:stretch;
    gap:4px;
    background:rgba(10,10,11,0.97);
    backdrop-filter:blur(16px);
    border-bottom:1px solid var(--color-border);
    padding:12px 16px 16px;
  }
  .nav-links.open{display:flex}
  .nav-links a{padding:10px 16px;font-size:15px}
  .nav-cta{display:none}
}

/* ═══════════════════════
   HERO
═══════════════════════ */
#hero{
  padding:0;
  min-height:100vh;
  display:flex;
  align-items:center;
  position:relative;
  overflow:hidden;
  background:var(--color-bg);
}

.hero-bg{
  position:absolute;
  inset:0;
  pointer-events:none;
  z-index:0;
}
.hero-bg::before{
  content:'';
  position:absolute;
  top:-20%;
  right:-10%;
  width:600px;
  height:600px;
  background:radial-gradient(circle,rgba(99,102,241,0.12) 0%,transparent 70%);
  border-radius:50%;
}
.hero-bg::after{
  content:'';
  position:absolute;
  bottom:10%;
  left:-5%;
  width:400px;
  height:400px;
  background:radial-gradient(circle,rgba(129,140,248,0.06) 0%,transparent 70%);
  border-radius:50%;
}

.hero-inner{
  position:relative;
  z-index:1;
  width:100%;
  max-width:var(--max-w);
  margin:0 auto;
  padding:128px 24px 96px;
  display:grid;
  grid-template-columns:1fr 380px;
  gap:64px;
  align-items:center;
}

.hero-content{display:flex;flex-direction:column;gap:0}

.hero-eyebrow{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-size:13px;
  font-weight:600;
  letter-spacing:0.1em;
  text-transform:uppercase;
  color:var(--color-primary);
  margin-bottom:24px;
}
.hero-eyebrow::before{
  content:'';
  display:block;
  width:24px;
  height:2px;
  background:var(--color-primary);
  border-radius:1px;
}

#hero h1{
  margin-bottom:24px;
  color:var(--color-text);
}
#hero h1 .accent{
  background:linear-gradient(135deg,var(--color-primary) 0%,var(--color-primary-light) 100%);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}

.hero-description{
  font-size:18px;
  color:var(--color-text-muted);
  line-height:1.65;
  max-width:560px;
  margin-bottom:40px;
}

.hero-stats{
  display:flex;
  gap:40px;
  margin-bottom:40px;
  padding:24px 0;
  border-top:1px solid var(--color-border);
  border-bottom:1px solid var(--color-border);
}

.hero-stat-number{
  font-size:28px;
  font-weight:800;
  color:var(--color-text);
  letter-spacing:-0.02em;
  line-height:1;
  margin-bottom:4px;
}
.hero-stat-label{
  font-size:12px;
  font-weight:500;
  color:var(--color-text-subtle);
  text-transform:uppercase;
  letter-spacing:0.06em;
}

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

.btn-primary{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-size:15px;
  font-weight:600;
  color:#fff;
  background:var(--color-primary);
  padding:12px 24px;
  border-radius:var(--radius-md);
  min-height:48px;
  transition:background 200ms var(--ease),transform 200ms var(--ease),box-shadow 200ms var(--ease);
  line-height:1.4;
}
.btn-primary:hover{
  background:var(--color-primary-light);
  transform:translateY(-2px);
  box-shadow:0 8px 24px rgba(99,102,241,0.4);
}
.btn-primary:active{transform:translateY(0)}

.btn-secondary{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-size:15px;
  font-weight:600;
  color:var(--color-text);
  background:rgba(255,255,255,0.06);
  border:1px solid var(--color-border-strong);
  padding:12px 24px;
  border-radius:var(--radius-md);
  min-height:48px;
  transition:background 200ms var(--ease),border-color 200ms var(--ease),transform 200ms var(--ease);
  line-height:1.4;
}
.btn-secondary:hover{
  background:rgba(255,255,255,0.1);
  border-color:rgba(255,255,255,0.25);
  transform:translateY(-2px);
}

/* HERO PHOTO */
.hero-photo{
  display:flex;
  justify-content:center;
  align-items:center;
}

.hero-photo-wrap{
  position:relative;
  width:320px;
  height:320px;
}

.hero-photo-wrap::before{
  content:'';
  position:absolute;
  inset:-3px;
  border-radius:50%;
  background:linear-gradient(135deg,var(--color-primary),var(--color-primary-light),transparent 60%);
  z-index:0;
}

.hero-photo-wrap img{
  position:relative;
  z-index:1;
  width:320px;
  height:320px;
  border-radius:50%;
  object-fit:cover;
  border:4px solid var(--color-bg);
  box-shadow:var(--shadow-glow),0 24px 64px rgba(0,0,0,0.6);
}

@media(max-width:1023px){
  .hero-inner{
    grid-template-columns:1fr;
    text-align:center;
    padding:120px 24px 80px;
    gap:48px;
  }
  .hero-eyebrow{justify-content:center}
  .hero-description{max-width:100%}
  .hero-stats{justify-content:center}
  .hero-actions{justify-content:center}
  .hero-photo{order:-1}
  .hero-photo-wrap{width:240px;height:240px}
  .hero-photo-wrap img{width:240px;height:240px}
  .hero-bg::before{width:400px;height:400px;top:-10%;right:-20%}
}

@media(max-width:639px){
  .hero-stats{gap:24px;flex-wrap:wrap;justify-content:space-around}
  .hero-photo-wrap{width:180px;height:180px}
  .hero-photo-wrap img{width:180px;height:180px}
}

/* ═══════════════════════
   ABOUT
═══════════════════════ */
#about{background:var(--color-bg-alt)}

.about-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:64px;
  align-items:start;
}

.about-text p{
  margin-bottom:20px;
  font-size:16px;
  line-height:1.75;
  color:var(--color-text-muted);
}
.about-text p:last-child{margin-bottom:0}

.value-cards{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:16px;
}

.value-card{
  background:var(--color-bg-card);
  border:1px solid var(--color-border);
  border-radius:var(--radius-lg);
  padding:24px;
  transition:border-color 200ms var(--ease),transform 200ms var(--ease),box-shadow 200ms var(--ease);
}
.value-card:hover{
  border-color:var(--color-primary-border);
  transform:translateY(-4px);
  box-shadow:var(--shadow-md),0 0 0 1px var(--color-primary-border);
}

.value-card-icon{
  font-size:20px;
  margin-bottom:12px;
  display:block;
}

.value-card h4{
  font-size:14px;
  font-weight:700;
  color:var(--color-text);
  margin-bottom:8px;
  letter-spacing:-0.005em;
}

.value-card p{
  font-size:13px;
  color:var(--color-text-subtle);
  line-height:1.55;
  margin:0;
}

@media(max-width:1023px){
  .about-grid{grid-template-columns:1fr;gap:40px}
}
@media(max-width:639px){
  .value-cards{grid-template-columns:1fr}
}

/* ═══════════════════════
   EXPERIENCE
═══════════════════════ */
#experience{background:var(--color-bg)}

.timeline{display:flex;flex-direction:column;gap:0}

.timeline-item{
  display:grid;
  grid-template-columns:220px 1fr;
  gap:40px;
  padding:40px 0;
  border-bottom:1px solid var(--color-border);
  position:relative;
}
.timeline-item:first-child{padding-top:0}
.timeline-item:last-child{border-bottom:none}

.timeline-company{
  padding-top:4px;
  position:sticky;
  top:80px;
  align-self:start;
}

.timeline-company h3{
  font-size:18px;
  font-weight:700;
  color:var(--color-text);
  margin-bottom:8px;
  letter-spacing:-0.01em;
}

.company-tag{
  display:inline-block;
  font-size:11px;
  font-weight:600;
  letter-spacing:0.06em;
  text-transform:uppercase;
  color:var(--color-text-subtle);
  background:rgba(255,255,255,0.05);
  border:1px solid var(--color-border);
  padding:3px 10px;
  border-radius:var(--radius-full);
}

.timeline-roles{display:flex;flex-direction:column;gap:24px}

.timeline-role{
  background:var(--color-bg-card);
  border:1px solid var(--color-border);
  border-radius:var(--radius-lg);
  padding:24px;
  transition:border-color 200ms var(--ease);
}
.timeline-role:hover{border-color:var(--color-primary-border)}

.timeline-role h4{
  font-size:15px;
  font-weight:600;
  color:var(--color-text);
  margin-bottom:6px;
  line-height:1.4;
}

.period{
  display:inline-flex;
  align-items:center;
  gap:6px;
  font-size:12px;
  font-weight:600;
  color:var(--color-primary);
  background:var(--color-primary-dim);
  border:1px solid var(--color-primary-border);
  padding:3px 10px;
  border-radius:var(--radius-full);
  margin-bottom:12px;
  letter-spacing:0.02em;
}

.timeline-role p{
  font-size:14px;
  color:var(--color-text-subtle);
  line-height:1.65;
  margin:0;
}

@media(max-width:767px){
  .timeline-item{
    grid-template-columns:1fr;
    gap:16px;
  }
  .timeline-company{position:static}
}

/* ═══════════════════════
   EDUCATION
═══════════════════════ */
#education{background:var(--color-bg-alt)}

.education-grid{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:24px;
}

.education-card{
  background:var(--color-bg-card);
  border:1px solid var(--color-border);
  border-radius:var(--radius-xl);
  padding:32px;
  position:relative;
  overflow:hidden;
  transition:border-color 200ms var(--ease),transform 200ms var(--ease),box-shadow 200ms var(--ease);
}
.education-card::before{
  content:'';
  position:absolute;
  top:0;
  left:0;
  right:0;
  height:3px;
  background:linear-gradient(90deg,var(--color-primary),var(--color-primary-light));
  opacity:0;
  transition:opacity 200ms var(--ease);
}
.education-card:hover{
  border-color:var(--color-primary-border);
  transform:translateY(-4px);
  box-shadow:var(--shadow-md);
}
.education-card:hover::before{opacity:1}

.education-degree{
  font-size:11px;
  font-weight:700;
  letter-spacing:0.1em;
  text-transform:uppercase;
  color:var(--color-primary);
  margin-bottom:12px;
}

.education-card h3{
  font-size:20px;
  font-weight:700;
  color:var(--color-text);
  margin-bottom:8px;
  letter-spacing:-0.01em;
}

.institution{
  font-size:14px;
  font-weight:600;
  color:var(--color-text-muted);
  margin-bottom:6px;
}

.year{
  font-size:13px;
  color:var(--color-primary);
  font-weight:600;
  margin-bottom:16px;
}

.thesis{
  font-size:13px;
  color:var(--color-text-muted);
  line-height:1.55;
  margin-bottom:8px;
  font-style:italic;
}

.thesis-meta{
  font-size:12px;
  color:var(--color-text-subtle);
  line-height:1.5;
}

@media(max-width:1023px){
  .education-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:639px){
  .education-grid{grid-template-columns:1fr}
}

/* ═══════════════════════
   PUBLICATIONS (RESEARCH)
═══════════════════════ */
#publications{background:var(--color-bg)}

.publications-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:16px;
}

.publication-card{
  background:var(--color-bg-card);
  border:1px solid var(--color-border);
  border-radius:var(--radius-lg);
  padding:24px;
  display:flex;
  flex-direction:column;
  gap:12px;
  transition:border-color 200ms var(--ease),transform 200ms var(--ease);
}
.publication-card:hover{
  border-color:var(--color-primary-border);
  transform:translateY(-2px);
}

.publication-card h4{
  font-size:15px;
  font-weight:600;
  color:var(--color-text);
  line-height:1.5;
  flex:1;
}

.publication-venue{
  font-size:13px;
  color:var(--color-text-subtle);
  line-height:1.4;
}

.publication-tag{
  display:inline-block;
  align-self:flex-start;
  font-size:11px;
  font-weight:700;
  letter-spacing:0.06em;
  text-transform:uppercase;
  color:var(--color-primary);
  background:var(--color-primary-dim);
  border:1px solid var(--color-primary-border);
  padding:3px 10px;
  border-radius:var(--radius-full);
}

@media(max-width:767px){
  .publications-grid{grid-template-columns:1fr}
}

/* ═══════════════════════
   SKILLS
═══════════════════════ */
#skills{background:var(--color-bg-alt)}

.skills-grid{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:24px;
}

.skill-group{
  background:var(--color-bg-card);
  border:1px solid var(--color-border);
  border-radius:var(--radius-xl);
  padding:32px;
  transition:border-color 200ms var(--ease);
}
.skill-group:hover{border-color:var(--color-primary-border)}

.skill-group h3{
  font-size:16px;
  font-weight:700;
  color:var(--color-text);
  margin-bottom:20px;
  padding-bottom:16px;
  border-bottom:1px solid var(--color-border);
  letter-spacing:-0.01em;
}

.skill-tags{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
}

.skill-tag{
  display:inline-block;
  font-size:12px;
  font-weight:600;
  color:var(--color-text-muted);
  background:rgba(255,255,255,0.05);
  border:1px solid var(--color-border-strong);
  padding:5px 12px;
  border-radius:var(--radius-full);
  transition:color 150ms var(--ease),background 150ms var(--ease),border-color 150ms var(--ease);
}
.skill-tag:hover{
  color:var(--color-text);
  background:var(--color-primary-dim);
  border-color:var(--color-primary-border);
}

@media(max-width:1023px){
  .skills-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:639px){
  .skills-grid{grid-template-columns:1fr}
}

/* ═══════════════════════
   CONTACT
═══════════════════════ */
#contact{
  background:var(--color-bg);
  position:relative;
  overflow:hidden;
}
#contact::before{
  content:'';
  position:absolute;
  bottom:-30%;
  left:50%;
  transform:translateX(-50%);
  width:800px;
  height:400px;
  background:radial-gradient(ellipse,rgba(99,102,241,0.08) 0%,transparent 70%);
  pointer-events:none;
}

.contact-inner{
  position:relative;
  z-index:1;
  text-align:center;
}

.contact-inner .section-label{margin:0 auto 16px}
.contact-inner .section-title{margin:0 auto 16px}
.contact-inner .section-subtitle{margin:0 auto 48px;max-width:500px}

.contact-links{
  display:flex;
  flex-wrap:wrap;
  gap:12px;
  justify-content:center;
}

.contact-link{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-size:14px;
  font-weight:600;
  color:var(--color-text-muted);
  background:var(--color-bg-card);
  border:1px solid var(--color-border);
  padding:14px 24px;
  border-radius:var(--radius-lg);
  min-height:48px;
  transition:color 200ms var(--ease),border-color 200ms var(--ease),background 200ms var(--ease),transform 200ms var(--ease),box-shadow 200ms var(--ease);
}
.contact-link:hover{
  color:var(--color-text);
  background:var(--color-bg-card-hover);
  border-color:var(--color-primary-border);
  transform:translateY(-3px);
  box-shadow:var(--shadow-md);
}
.contact-link svg{
  color:var(--color-primary);
  flex-shrink:0;
}

@media(max-width:639px){
  .contact-links{flex-direction:column;align-items:center}
  .contact-link{width:100%;max-width:320px;justify-content:center}
}

/* ═══════════════════════
   FOOTER
═══════════════════════ */
footer{
  background:var(--color-bg-alt);
  border-top:1px solid var(--color-border);
  padding:32px 0;
}

.footer-inner{
  width:100%;
  max-width:var(--max-w);
  margin:0 auto;
  padding:0 24px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  flex-wrap:wrap;
  gap:16px;
}

.footer-brand{
  font-size:15px;
  font-weight:700;
  color:var(--color-text);
  letter-spacing:-0.01em;
}

.footer-location{
  font-size:13px;
  color:var(--color-text-subtle);
  font-weight:500;
}

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

.footer-nav a{
  font-size:13px;
  font-weight:500;
  color:var(--color-text-subtle);
  padding:4px 8px;
  border-radius:var(--radius-sm);
  transition:color 150ms var(--ease);
}
.footer-nav a:hover{color:var(--color-primary-light)}

@media(max-width:767px){
  .footer-inner{flex-direction:column;text-align:center}
  .footer-nav{flex-wrap:wrap;justify-content:center}
}

/* ═══════════════════════
   FADE IN ANIMATION
═══════════════════════ */
.fade-in{
  opacity:0;
  transform:translateY(20px);
  transition:opacity 600ms var(--ease),transform 600ms var(--ease);
}
.fade-in.visible{
  opacity:1;
  transform:translateY(0);
}