:root {
  --primary: #1e3a5f;
  --primary-light: #2c5282;
  --accent: #3182ce;
  --text-dark: #2d3748;
  --text-light: #4a5568;
  --bg-light: #f7fafc;
  --bg-white: #ffffff;
  --border: #e2e8f0;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  color: var(--text-dark);
  background: var(--bg-white);
}

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

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

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 24px;
}

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

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 0;
}

.nav-brand {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--primary);
}

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

.nav-links a {
  color: var(--text-light);
  font-weight: 500;
  font-size: 0.95rem;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
}

.hero {
  padding: 64px 0;
  border-bottom: 1px solid var(--border);
}

.hero-content {
  display: flex;
  gap: 48px;
  align-items: flex-start;
}

.hero-photo {
  flex-shrink: 0;
}

.hero-photo img {
  width: 250px;
  height: 270px;
  object-fit: cover;
  border-radius: 8px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

.hero-text {
  flex: 1;
}

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

.hero-text h1 {
  font-size: 2rem;
  color: var(--primary);
  margin-bottom: 16px;
}

.hero-text p {
  color: var(--text-light);
  margin-bottom: 20px;
}

.hero-links {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.hero-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--primary);
  color: white;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.2s;
}

.hero-links a:hover {
  background: var(--primary-light);
  color: white;
}

section {
  padding: 56px 0;
  border-bottom: 1px solid var(--border);
}

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

.section-title {
  font-size: 1.4rem;
  color: var(--primary);
  margin-bottom: 28px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--primary);
  display: inline-block;
}

.paper {
  margin-bottom: 28px;
  padding-left: 20px;
  border-left: 3px solid var(--border);
  transition: border-color 0.2s;
}

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

.paper-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 6px;
}

.paper-title a {
  color: inherit;
}

.paper-title a:hover {
  color: var(--accent);
}

.paper-authors {
  color: var(--text-light);
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.paper-meta {
  color: var(--text-light);
  font-size: 0.9rem;
}

.paper-meta .journal {
  font-style: italic;
}

.status-badge {
  display: inline-block;
  padding: 2px 8px;
  background: #ebf8ff;
  color: var(--accent);
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 500;
  margin-left: 8px;
}

.conferences {
  font-size: 0.85rem;
  color: var(--text-light);
  margin-top: 4px;
}

#download-section {
  padding: 16px 0;
  margin-bottom: 28px;
}

#download-form-ui {
  display: none;
  margin-top: 20px;
  padding: 24px;
  background: white;
  border-radius: 8px;
  border: 1px solid var(--border);
}

#download-form-ui label {
  display: block;
  margin-bottom: 4px;
  font-weight: 500;
  font-size: 0.9rem;
}

#download-form-ui input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.95rem;
  margin-bottom: 12px;
}

#download-form-ui input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.1);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 500;
  transition: background 0.2s;
}

.btn:hover {
  background: var(--primary-light);
  color: white;
}

.btn-secondary {
  background: var(--primary);
}

.success-msg {
  padding: 16px;
  background: #f0fff4;
  border: 1px solid #9ae6b4;
  border-radius: 6px;
  color: #276749;
}

footer {
  background: var(--primary);
  color: white;
  padding: 40px 0;
  margin-top: auto;
}

footer a {
  color: rgba(255,255,255,0.8);
}

footer a:hover {
  color: white;
}

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

.footer-info p {
  font-size: 0.9rem;
  opacity: 0.9;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  font-size: 0.9rem;
}

.page-header {
  padding: 48px 0 32px;
  border-bottom: 1px solid var(--border);
}

.page-header h1 {
  font-size: 2rem;
  color: var(--primary);
}

.page-header p {
  color: var(--text-light);
  margin-top: 8px;
}

.software-list {
  list-style: none;
}

.software-item {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}

.software-item:last-child {
  border-bottom: none;
}

.software-item h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.software-item h3 a {
  color: var(--accent);
}

.software-item p {
  color: var(--text-light);
  font-size: 0.95rem;
}

.teaching-item {
  margin-bottom: 40px;
}

.teaching-item h3 {
  font-size: 1.15rem;
  color: var(--primary);
  margin-bottom: 12px;
}

.teaching-item .links {
  display: flex;
  gap: 16px;
  margin-bottom: 16px;
}

.teaching-item .links a {
  font-size: 0.9rem;
}

blockquote {
  background: var(--bg-light);
  padding: 16px 20px;
  border-radius: 6px;
  margin-top: 12px;
  font-size: 0.9rem;
  color: var(--text-light);
}

blockquote p {
  margin-bottom: 8px;
}

blockquote p:last-child {
  margin-bottom: 0;
}

.feedback-list {
  list-style: none;
  display: grid;
  gap: 12px;
}

.feedback-list li {
  padding: 12px 16px;
  background: var(--bg-light);
  border-radius: 6px;
  font-size: 0.9rem;
  color: var(--text-light);
  border-left: 3px solid var(--accent);
}

@media (max-width: 768px) {
  .hero-content {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .hero-links {
    justify-content: center;
  }

  .nav-links {
    gap: 20px;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .footer-content {
    flex-direction: column;
    gap: 20px;
    text-align: center;
  }
}