:root {
  --bg-light: #f5f7fa;
  --bg-white: #ffffff;
  --text-dark: #1a1a1a;
  --text-muted: #666666;
  --accent-blue: #0066ff;
  --accent-light-blue: #e6f0ff;
  --border-color: #e0e0e0;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', sans-serif;
  background-color: var(--bg-light);
  color: var(--text-dark);
  line-height: 1.6;
  font-size: 16px;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

h1 { font-size: 3.5rem; font-weight: 700; line-height: 1.2; margin-bottom: 1.5rem; }
h2 { font-size: 2.5rem; font-weight: 700; margin-bottom: 1rem; }
h3 { font-size: 1.25rem; font-weight: 600; }

p { color: var(--text-muted); margin-bottom: 1rem; }

a { color: var(--accent-blue); text-decoration: none; transition: color 0.3s; }
a:hover { color: #0052cc; }

.navbar {
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem 2rem;
}

.logo {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2.5rem;
}

.nav-links a {
  font-size: 0.95rem;
  color: var(--text-muted);
}

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

.hero {
  background-color: var(--bg-white);
  padding: 6rem 0;
  border-bottom: 1px solid var(--border-color);
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.location {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
  font-size: 0.95rem;
}

.dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-blue);
  border-radius: 50%;
}

.hero h1 {
  margin-bottom: 1.5rem;
  line-height: 1.3;
}

.hero-description {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  line-height: 1.7;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  margin-top: 2rem;
}

.btn {
  padding: 0.75rem 1.5rem;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
  display: inline-block;
  border: none;
}

.btn-primary {
  background-color: var(--accent-blue);
  color: white;
}

.btn-primary:hover {
  background-color: #0052cc;
}

.btn-outline {
  border: 2px solid var(--accent-blue);
  color: var(--accent-blue);
  background-color: transparent;
}

.btn-outline:hover {
  background-color: var(--accent-light-blue);
}

.hero-card {
  background-color: var(--accent-light-blue);
  border-radius: 12px;
  padding: 2rem;
  height: fit-content;
}

.profile-section {
  text-align: center;
}

.profile-section h3 {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.role-badge {
  display: inline-block;
  background-color: var(--accent-blue);
  color: white;
  padding: 0.4rem 0.8rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.profile-section p {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

section {
  padding: 5rem 0;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
}

section:last-child {
  border-bottom: none;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 3rem;
  max-width: 600px;
}

.experience-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.experience-card {
  background-color: var(--bg-light);
  padding: 2rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  transition: all 0.3s;
}

.experience-card:hover {
  border-color: var(--accent-blue);
  box-shadow: 0 4px 12px rgba(0, 102, 255, 0.1);
}

.experience-card h3 {
  margin-bottom: 0.5rem;
}

.role {
  font-size: 0.95rem;
  color: var(--accent-blue);
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.date {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.description {
  font-size: 0.95rem;
  line-height: 1.6;
}

.expertise-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.expertise-item {
  background-color: var(--bg-light);
  padding: 1.5rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  text-align: center;
  font-weight: 500;
  color: var(--text-dark);
  transition: all 0.3s;
}

.expertise-item:hover {
  background-color: var(--accent-light-blue);
  border-color: var(--accent-blue);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.project-card {
  background-color: var(--bg-light);
  padding: 2rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  transition: all 0.3s;
}

.project-card:hover {
  border-color: var(--accent-blue);
  box-shadow: 0 4px 12px rgba(0, 102, 255, 0.1);
}

.project-card h3 {
  margin-bottom: 1rem;
}

.project-card p {
  font-size: 0.95rem;
  margin-bottom: 1rem;
}

.tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.tag {
  background-color: var(--accent-light-blue);
  color: var(--accent-blue);
  padding: 0.35rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
}

.research-list {
  margin-top: 2rem;
}

.research-item {
  background-color: var(--bg-light);
  padding: 2rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
  transition: all 0.3s;
}

.research-item:hover {
  border-color: var(--accent-blue);
  box-shadow: 0 4px 12px rgba(0, 102, 255, 0.1);
}

.research-item h3 {
  margin-bottom: 0.5rem;
}

.venue {
  font-size: 0.9rem;
  color: var(--accent-blue);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.contact-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  margin-top: 3rem;
}

.contact-form {
  background-color: var(--bg-light);
  padding: 2rem;
  border-radius: 8px;
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-dark);
  font-size: 0.95rem;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-family: inherit;
  font-size: 0.95rem;
  transition: border-color 0.3s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.contact-links {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.contact-link p {
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 0.5rem;
}

.contact-link a {
  font-size: 1rem;
  color: var(--accent-blue);
}

.footer {
  background-color: var(--bg-light);
  padding: 2rem 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
}

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

@media (max-width: 768px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 1.8rem; }
  .hero .container { grid-template-columns: 1fr; }
  .nav-links { gap: 1.5rem; }
  .cta-buttons { flex-direction: column; }
  .btn { width: 100%; text-align: center; }
  .contact-content { grid-template-columns: 1fr; }
  .hero { padding: 3rem 0; }
  section { padding: 3rem 0; }
}

@media (max-width: 480px) {
  .container { padding: 0 1rem; }
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  .navbar .container { flex-direction: column; gap: 1rem; padding: 1rem; }
  .nav-links { flex-direction: column; gap: 0.5rem; width: 100%; }
  .nav-links a { display: block; padding: 0.5rem 0; }
}