/* Modern Academic Portfolio Stylesheet */
/* Mei Wang - Personal Homepage */

:root {
  --primary: #2d5a6b;
  --primary-light: #4a8a9b;
  --accent: #e07a5f;
  --accent-light: #f2a892;
  --bg-dark: #f8f6f4;
  --bg-card: #ffffff;
  --text-primary: #2d3748;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --border: #e2e8f0;
  --gradient-start: #e8f4f6;
  --gradient-end: #faf5f3;
  --success: #48bb78;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-light);
}

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

/* Navigation */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(248, 246, 244, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  padding: 16px 0;
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav .logo {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text-primary);
}

nav ul {
  display: flex;
  list-style: none;
  gap: 32px;
}

nav ul a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

nav ul a:hover {
  color: var(--text-primary);
}

/* Hamburger menu for mobile */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
}

.hamburger span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: 0.3s;
}

/* Hero Section */
.hero {
  padding: 160px 0 80px;
  text-align: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
}

.profile-img {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--accent);
  box-shadow: var(--shadow-lg);
}

.hero h1 {
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.hero .tagline {
  font-size: 1.25rem;
  color: var(--accent-light);
  font-weight: 500;
  margin-bottom: 8px;
}

.hero .subtitle {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 600px;
}

.contact-links {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 16px;
}

.contact-links a {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  padding: 10px 20px;
  border-radius: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  transition: all 0.2s ease;
}

.contact-links a:hover {
  background: var(--primary-light);
  color: var(--text-primary);
  border-color: var(--accent);
  transform: translateY(-2px);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--accent), var(--primary-light));
  color: white;
  padding: 12px 28px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.2s ease;
  box-shadow: var(--shadow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  color: white;
}

/* Section Styles */
section {
  padding: 80px 0;
}

section h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 40px;
  position: relative;
  display: inline-block;
}

section h2::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 0;
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), transparent);
  border-radius: 2px;
}

/* About Section */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-size: 1.05rem;
}

.research-interests {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.research-interests span {
  background: var(--bg-card);
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 0.9rem;
  color: var(--accent-light);
  border: 1px solid var(--border);
}

/* Experience Section */
.experience-item {
  background: var(--bg-card);
  border-radius: 16px;
  padding: 32px;
  margin-bottom: 24px;
  border: 1px solid var(--border);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.experience-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.experience-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 12px;
}

.experience-header h3 {
  font-size: 1.25rem;
  color: var(--text-primary);
}

.experience-header .company {
  color: var(--accent);
  font-weight: 500;
}

.experience-header .date {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.experience-item ul {
  list-style: none;
  margin-top: 16px;
}

.experience-item li {
  position: relative;
  padding-left: 20px;
  margin-bottom: 12px;
  color: var(--text-secondary);
}

.experience-item li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* Publications Section */
.publication-list {
  counter-reset: pub-counter;
}

.publication {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 16px;
  border: 1px solid var(--border);
  transition: all 0.2s ease;
  position: relative;
  padding-left: 60px;
}

.publication::before {
  counter-increment: pub-counter;
  content: "[" counter(pub-counter) "]";
  position: absolute;
  left: 20px;
  top: 24px;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.9rem;
}

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

.publication .title {
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.4;
}

.publication .authors {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 8px;
}

.publication .authors .me {
  color: var(--accent-light);
  font-weight: 600;
}

.publication .venue {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.publication .venue-name {
  background: var(--primary-light);
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

.publication .year {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.publication .award {
  display: inline-block;
  background: linear-gradient(135deg, #f59e0b, #d97706);
  color: white;
  padding: 2px 10px;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-left: 8px;
}

/* Education Section */
.education-grid {
  display: grid;
  gap: 24px;
}

.education-item {
  background: var(--bg-card);
  border-radius: 16px;
  padding: 28px;
  border: 1px solid var(--border);
  display: flex;
  gap: 24px;
  align-items: flex-start;
}

.education-item .icon {
  font-size: 2rem;
  flex-shrink: 0;
}

.education-item h3 {
  font-size: 1.15rem;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.education-item .school {
  color: var(--accent);
  font-weight: 500;
  margin-bottom: 4px;
}

.education-item .date {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.education-item .advisor {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 8px;
}

/* Awards Section */
.awards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.award-item {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 24px;
  border: 1px solid var(--border);
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.award-item .icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.award-item h4 {
  font-size: 1rem;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.award-item .year {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Skills Section */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.skill-category {
  background: var(--bg-card);
  border-radius: 16px;
  padding: 28px;
  border: 1px solid var(--border);
}

.skill-category h3 {
  font-size: 1.1rem;
  color: var(--accent-light);
  margin-bottom: 16px;
  font-weight: 600;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.skill-tags span {
  background: rgba(224, 122, 95, 0.12);
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  border: 1px solid rgba(224, 122, 95, 0.2);
}

/* Footer */
footer {
  padding: 40px 0;
  text-align: center;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 768px) {
  nav ul {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-dark);
    flex-direction: column;
    padding: 20px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
  }

  nav ul.active {
    display: flex;
  }

  .hamburger {
    display: flex;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero .tagline {
    font-size: 1.1rem;
  }

  .about-content {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .experience-header {
    flex-direction: column;
  }

  .education-item {
    flex-direction: column;
    text-align: center;
  }

  .contact-links {
    flex-direction: column;
    align-items: center;
  }

  .publication {
    padding-left: 24px;
  }

  .publication::before {
    position: static;
    display: block;
    margin-bottom: 8px;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 120px 0 60px;
  }

  .profile-img {
    width: 140px;
    height: 140px;
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  section {
    padding: 60px 0;
  }

  section h2 {
    font-size: 1.5rem;
  }
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.6s ease forwards;
}