/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #fff;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Removed old header/nav styles - now using shared navbar.css */

/* Hero Section */
.hero {
  padding: 4rem 2rem;
  background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

.hero__content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 3rem;
  align-items: center;
}

.hero__text h1 {
  font-size: 3rem;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 1rem;
}

.hero__subtitle {
  font-size: 1.25rem;
  color: #64748b;
  margin-bottom: 2rem;
  line-height: 1.7;
}

.hero__stats {
  display: flex;
  gap: 2rem;
  margin-bottom: 2rem;
}

.stat {
  text-align: center;
}

.stat__number {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: #2563eb;
}

.stat__label {
  display: block;
  font-size: 0.875rem;
  color: #6b7280;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero__actions {
  display: flex;
  gap: 1rem;
}

.hero__image {
  display: flex;
  justify-content: center;
}

.profile-photo {
  width: 280px;
  height: 280px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid #fff;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.3s ease;
  cursor: pointer;
  border: 2px solid transparent;
}

.btn--primary {
  background: #2563eb;
  color: #fff;
}

.btn--primary:hover {
  background: #1d4ed8;
  transform: translateY(-2px);
}

.btn--secondary {
  background: transparent;
  color: #2563eb;
  border-color: #2563eb;
}

.btn--secondary:hover {
  background: #2563eb;
  color: #fff;
}

.btn--outline {
  background: transparent;
  color: #374151;
  border-color: #d1d5db;
}

.btn--outline:hover {
  background: #f9fafb;
  border-color: #2563eb;
  color: #2563eb;
}

/* Sections */
section {
  padding: 4rem 0;
}

h2 {
  font-size: 2.5rem;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 1rem;
  text-align: center;
}

.section-subtitle {
  font-size: 1.125rem;
  color: #64748b;
  text-align: center;
  margin-bottom: 3rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* About Section */
.about {
  background: #f8fafc;
}

.about__content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  margin-top: 2rem;
}

.about__text p {
  font-size: 1.125rem;
  color: #4b5563;
  margin-bottom: 1.5rem;
}

.about__skills h3 {
  font-size: 1.5rem;
  color: #1e293b;
  margin-bottom: 1.5rem;
}

.skills-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.skill-category h4 {
  font-size: 1.125rem;
  color: #374151;
  margin-bottom: 0.75rem;
}

.skill-category ul {
  list-style: none;
}

.skill-category li {
  padding: 0.5rem 0;
  color: #6b7280;
  border-bottom: 1px solid #e5e7eb;
}

.skill-category li:last-child {
  border-bottom: none;
}

/* Research Section */
.research {
  padding: 4rem 0;
}

.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.paper-card {
  background: #fff;
  border-radius: 0.75rem;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  padding: 2rem;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.paper-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.paper-card__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.paper-card__header h3 {
  font-size: 1.25rem;
  color: #1e293b;
  flex: 1;
}

.paper-card__type {
  background: #dbeafe;
  color: #1d4ed8;
  padding: 0.25rem 0.75rem;
  border-radius: 1rem;
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.paper-card__content p {
  color: #6b7280;
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.paper-card__meta {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.meta-item {
  font-size: 0.875rem;
  color: #9ca3af;
  padding: 0.25rem 0.5rem;
  background: #f3f4f6;
  border-radius: 0.25rem;
}

.paper-card__actions {
  text-align: center;
}

/* Contact Section */
.contact {
  background: #f8fafc;
  padding: 4rem 0;
}

.contact__content {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3rem;
  align-items: center;
  margin-top: 2rem;
}

.contact__info {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.contact-item h3 {
  font-size: 1.25rem;
  color: #1e293b;
  margin-bottom: 0.75rem;
}

.contact-item p {
  color: #6b7280;
  margin-bottom: 0.5rem;
}

/* Footer */
.footer {
  background: #1e293b;
  color: #94a3b8;
  text-align: center;
  padding: 2rem 0;
}

/* Responsive Design */
@media (max-width: 768px) {
  .hero__content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .hero__text h1 {
    font-size: 2rem;
  }
  
  .profile-photo {
    width: 200px;
    height: 200px;
  }
  
  .about__content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  .skills-grid {
    grid-template-columns: 1fr;
  }
  
  .papers-grid {
    grid-template-columns: 1fr;
  }
  
  .contact__content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .contact__info {
    grid-template-columns: 1fr;
  }
  
  .hero__actions {
    justify-content: center;
    flex-wrap: wrap;
  }
}