:root{
  --bg:#0f1724;
  --card:#0b1220;
  --muted:#9aa5b1;
  --accent:#7dd3fc;
  --text:#e6eef6;
  --navbar-height:60px;
}

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

html{
  scroll-behavior:smooth;
}

html,body{
  height:100%;
}

body{
  margin:0;
  font-family:Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  background:linear-gradient(180deg,var(--bg), #071028);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  line-height:1.6;
  padding-top:calc(var(--navbar-height) + 10px);
}

/* Navigation Bar */
.navbar{
  position:fixed;
  top:0;
  left:0;
  right:0;
  background:rgba(15, 23, 36, 0.95);
  backdrop-filter:blur(10px);
  border-bottom:1px solid rgba(125, 211, 252, 0.1);
  z-index:1000;
  box-shadow:0 2px 10px rgba(0, 0, 0, 0.3);
}

.nav-container{
  max-width:1200px;
  margin:0 auto;
  padding:0 28px;
  display:flex;
  justify-content:space-between;
  align-items:center;
  height:var(--navbar-height);
}

.nav-brand{
  font-size:1.2rem;
  font-weight:600;
  color:var(--accent);
}

.nav-menu{
  display:flex;
  list-style:none;
  gap:32px;
  margin:0;
  padding:0;
}

.nav-menu a{
  color:var(--text);
  text-decoration:none;
  font-weight:500;
  transition:color 0.3s ease;
  position:relative;
  padding:4px 0;
}

.nav-menu a::after{
  content:'';
  position:absolute;
  bottom:0;
  left:0;
  width:0;
  height:2px;
  background:var(--accent);
  transition:width 0.3s ease;
}

.nav-menu a:hover{
  color:var(--accent);
}

.nav-menu a:hover::after{
  width:100%;
}

.nav-menu a:focus{
  outline:2px solid var(--accent);
  outline-offset:4px;
  border-radius:2px;
}

.nav-toggle{
  display:none;
  flex-direction:column;
  background:transparent;
  border:none;
  cursor:pointer;
  padding:8px;
  gap:4px;
}

.nav-toggle span{
  width:25px;
  height:3px;
  background:var(--text);
  transition:all 0.3s ease;
  border-radius:2px;
}

.nav-toggle.active span:nth-child(1){
  transform:rotate(45deg) translate(7px, 7px);
}

.nav-toggle.active span:nth-child(2){
  opacity:0;
}

.nav-toggle.active span:nth-child(3){
  transform:rotate(-45deg) translate(7px, -7px);
}

/* Container */
.container{
  max-width:1100px;
  margin:48px auto;
  padding:40px 28px;
  background:rgba(255,255,255,0.02);
  border-radius:16px;
  box-shadow:0 4px 24px rgba(0, 0, 0, 0.2);
}

/* Header */
.site-header{
  text-align:center;
  padding:40px 0;
  border-bottom:1px solid rgba(255,255,255,0.05);
  margin-bottom:40px;
}

.site-header h1{
  margin:16px 0 8px 0;
  font-size:2.5rem;
  font-weight:700;
  background:linear-gradient(135deg, var(--text), var(--accent));
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}

.subtitle{
  color:var(--muted);
  margin:8px 0 16px 0;
  font-size:1.1rem;
  line-height:1.5;
}

.profile-photo {
  width:160px;
  height:160px;
  border-radius:50%;
  object-fit:cover;
  margin-bottom:24px;
  border:4px solid var(--accent);
  box-shadow:0 8px 16px rgba(125, 211, 252, 0.2);
  transition:transform 0.3s ease, box-shadow 0.3s ease;
}

.profile-photo:hover{
  transform:scale(1.05);
  box-shadow:0 12px 24px rgba(125, 211, 252, 0.3);
}

.links{
  margin:16px 0;
}

.links a{
  color:var(--accent);
  text-decoration:none;
  font-size:1.05rem;
  transition:color 0.3s ease, text-shadow 0.3s ease;
}

.links a:hover{
  color:#a5e7ff;
  text-shadow:0 0 8px rgba(125, 211, 252, 0.5);
}

.links a:focus{
  outline:2px solid var(--accent);
  outline-offset:4px;
  border-radius:2px;
}

/* Social Links */
.social-links{
  display:flex;
  gap:20px;
  justify-content:center;
  margin-top:20px;
}

.social-link{
  color:var(--muted);
  transition:all 0.3s ease;
  padding:8px;
  border-radius:8px;
  display:flex;
  align-items:center;
  justify-content:center;
}

.social-link:hover{
  color:var(--accent);
  background:rgba(125, 211, 252, 0.1);
  transform:translateY(-2px);
}

.social-link:focus{
  outline:2px solid var(--accent);
  outline-offset:4px;
  border-radius:8px;
}

.social-link svg{
  width:24px;
  height:24px;
}

/* Main Content */
main{
  margin-top:0;
}

section{
  padding:40px 0;
  border-top:1px solid rgba(255,255,255,0.05);
  opacity:0;
  transform:translateY(20px);
  transition:opacity 0.6s ease, transform 0.6s ease;
}

section.fade-in{
  opacity:1;
  transform:translateY(0);
}

section:first-child{
  border-top:none;
}

section h2{
  margin:0 0 24px 0;
  font-size:2rem;
  font-weight:700;
  color:var(--accent);
  position:relative;
  padding-bottom:12px;
}

section h2::after{
  content:'';
  position:absolute;
  bottom:0;
  left:0;
  width:60px;
  height:3px;
  background:linear-gradient(90deg, var(--accent), transparent);
}

section p{
  margin:0 0 16px 0;
  line-height:1.8;
  color:var(--text);
  font-size:1.05rem;
}

section p.bio{
  color:var(--muted);
  font-size:1rem;
}

section a{
  color:var(--accent);
  text-decoration:none;
  transition:color 0.3s ease;
  border-bottom:1px solid transparent;
}

section a:hover{
  color:#a5e7ff;
  border-bottom-color:var(--accent);
}

section a:focus{
  outline:2px solid var(--accent);
  outline-offset:2px;
  border-radius:2px;
}

/* PhD Projects Grid */
.phd-projects-grid{
  display:grid;
  gap:24px;
  margin-top:32px;
}

.project-card{
  background:var(--card);
  border:1px solid rgba(125, 211, 252, 0.1);
  border-radius:12px;
  padding:28px;
  transition:all 0.3s ease;
  opacity:0;
  transform:translateY(20px);
  box-shadow:0 2px 8px rgba(0, 0, 0, 0.2);
}

.project-card.fade-in{
  opacity:1;
  transform:translateY(0);
}

.project-card:hover{
  border-color:rgba(125, 211, 252, 0.3);
  box-shadow:0 8px 24px rgba(125, 211, 252, 0.1);
  transform:translateY(-4px);
}

.project-card h3{
  margin:0 0 16px 0;
  font-size:1.3rem;
  color:var(--accent);
  font-weight:600;
}

.project-card p{
  margin:0;
  color:var(--muted);
  line-height:1.7;
}

/* Footer */
footer{
  margin-top:48px;
  padding-top:32px;
  border-top:1px solid rgba(255,255,255,0.05);
  color:var(--muted);
  font-size:0.95rem;
  text-align:center;
}

/* Responsive Design */
@media (max-width:900px){
  .container{
    margin:32px 20px;
    padding:32px 24px;
  }
  
  .site-header h1{
    font-size:2rem;
  }
  
  section h2{
    font-size:1.6rem;
  }
  
  .project-card{
    padding:24px;
  }
}

@media (max-width:600px){
  body{
    padding-top:calc(var(--navbar-height) + 0px);
  }
  
  .nav-toggle{
    display:flex;
  }
  
  .nav-menu{
    position:absolute;
    top:var(--navbar-height);
    left:0;
    right:0;
    flex-direction:column;
    background:rgba(15, 23, 36, 0.98);
    backdrop-filter:blur(10px);
    padding:20px 28px;
    gap:16px;
    transform:translateY(-100%);
    opacity:0;
    visibility:hidden;
    transition:all 0.3s ease;
    border-bottom:1px solid rgba(125, 211, 252, 0.1);
  }
  
  .nav-menu.active{
    transform:translateY(0);
    opacity:1;
    visibility:visible;
  }
  
  .nav-menu a{
    padding:12px 0;
    font-size:1.1rem;
  }
  
  .container{
    margin:20px 16px;
    padding:24px 20px;
  }
  
  .site-header{
    padding:24px 0;
  }
  
  .site-header h1{
    font-size:1.8rem;
  }
  
  .subtitle{
    font-size:1rem;
  }
  
  .profile-photo{
    width:120px;
    height:120px;
  }
  
  section{
    padding:28px 0;
  }
  
  section h2{
    font-size:1.5rem;
  }
  
  section p{
    font-size:1rem;
  }
  
  .project-card{
    padding:20px;
  }
  
  .project-card h3{
    font-size:1.15rem;
  }
  
  .social-links{
    gap:16px;
  }
  
  .social-link svg{
    width:20px;
    height:20px;
  }
}