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

html { height: 100%; }

body {
  height: 100%;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  margin: 0;
  padding: 0 20px 60px 20px;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: white;
  font-size: 16px;
  line-height: 1.65;
  color: #333;
}

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

/* -- Navigation -- */
.site-nav {
  background: #fff;
  margin: 0 -20px 36px -20px;
  width: calc(100% + 40px);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid #e0e0e0;
}

.nav-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-name {
  color: #0056b3;
  font-weight: 600;
  font-size: 15px;
  padding: 16px 0;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.nav-links {
  display: flex;
}

.nav-links a {
  color: #555;
  text-decoration: none;
  padding: 14px 18px;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
  border-bottom: 2px solid transparent;
}

.nav-links a.active {
  color: #0056b3;
  border-bottom-color: #0056b3;
}

.nav-links a:hover {
  color: #0056b3;
}

/* -- Header / Bio -- */
.header-section {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 36px;
  margin-bottom: 44px;
  align-items: start;
}

.profile-photo {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center 12%;
}

.header-content h1 {
  font-size: 38px;
  font-weight: 600;
  margin: 0 0 8px 0;
  color: #0056b3;
}

.header-content .title {
  font-size: 17px;
  color: #666;
  margin-bottom: 6px;
  font-style: italic;
}

.research-interests {
  font-size: 13px;
  color: #888;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.header-content .title a {
  color: #666;
  text-decoration: none;
}

.header-content .title a:hover {
  color: #0056b3;
  text-decoration: underline;
}

.intro-text {
  line-height: 1.7;
  margin-bottom: 14px;
  color: #333;
}

.intro-text:last-child { margin-bottom: 0; }

.intro-text a {
  color: #0056b3;
  text-decoration: none;
}

.intro-text a:hover { text-decoration: underline; }

/* -- Working Papers -- */
.research-focus {
  margin: 0 0 44px 0;
}

.research-focus h2,
.updates-section > h2,
.contact-section > h2 {
  font-size: 18px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: #333;
  margin-bottom: 16px;
  border-bottom: 1px solid #e0e0e0;
  padding-bottom: 8px;
}

.papers-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.paper-item {
  font-size: 15px;
  line-height: 1.55;
}

.paper-title-line {
  font-weight: 600;
  color: #222;
  margin-bottom: 4px;
}

.paper-date {
  font-weight: 400;
  color: #888;
  font-size: 14px;
}

.paper-coauthor {
  font-weight: 400;
  color: #555;
  font-size: 14px;
}

.paper-coauthor a {
  color: #0056b3;
  text-decoration: none;
}

.paper-coauthor a:hover { text-decoration: underline; }

.paper-toggle {
  margin-top: 4px;
}

.paper-toggle summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  user-select: none;
}

.paper-toggle summary::-webkit-details-marker { display: none; }

.abstract-btn {
  font-size: 12px;
  color: #0056b3;
  border: 1px solid #0056b3;
  padding: 2px 8px;
  border-radius: 3px;
  font-weight: 500;
  letter-spacing: 0.02em;
}

.paper-action-btn {
  font-size: 12px;
  color: #fff;
  background: #0056b3;
  padding: 2px 8px;
  border-radius: 3px;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-decoration: none;
}

.paper-action-btn:hover { background: #003d80; }

.paper-action-btn.muted {
  background: #999;
  color: #fff;
  cursor: default;
}

.paper-toggle p {
  margin-top: 10px;
  font-size: 14px;
  line-height: 1.6;
  color: #444;
  padding-left: 2px;
}

/* -- Recent Updates -- */
.updates-section {
  margin-bottom: 44px;
}

.updates-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
}

.update-category h3 {
  font-size: 15px;
  font-weight: 600;
  color: #333;
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.update-item {
  margin-bottom: 12px;
  font-size: 15px;
  line-height: 1.55;
  color: #444;
}

.update-item:last-child { margin-bottom: 0; }

.update-item a {
  color: #0056b3;
  text-decoration: none;
}

.update-item a:hover { text-decoration: underline; }

.update-date {
  font-weight: 500;
  color: #555;
}

/* -- Contact -- */
.contact-section {
  margin-top: 44px;
  padding-top: 24px;
  border-top: 1px solid #e0e0e0;
}

.contact-info {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}

.contact-info div {
  font-size: 15px;
  line-height: 1.7;
  color: #444;
}

.contact-info a {
  color: #0056b3;
  text-decoration: none;
}

.contact-info a:hover { text-decoration: underline; }

/* -- Footer -- */
.site-footer {
  max-width: 900px;
  margin: 48px auto 0;
  padding: 16px 0 0;
  border-top: 1px solid #e0e0e0;
  font-size: 12px;
  color: #999;
  font-style: italic;
  text-align: center;
}

/* -- Mobile -- */
@media (max-width: 768px) {
  .nav-name { display: none; }

  .nav-inner { padding: 0; }

  .nav-links {
    flex: 1;
    width: 100%;
  }

  .nav-links a {
    flex: 1;
    text-align: center;
    padding: 12px 0;
  }

  .header-section {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .profile-photo {
    width: 150px;
    height: 150px;
    margin: 0 auto;
  }

  .updates-grid,
  .contact-info {
    grid-template-columns: 1fr;
  }
}