:root {
  --primary-color: #1a73e8;
  --text-color: #202124;
  --muted-color: #5f6368;
  --background-color: #ffffff;
  --border-color: #dadce0;
  --card-background: #f8f9fa;
  font-size: 16px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Roboto', 'Arial', sans-serif;
  color: var(--text-color);
  background: var(--background-color);
  line-height: 1.6;
}

a {
  color: var(--primary-color);
  text-decoration: none;
}

a:hover,
a:focus {
  text-decoration: underline;
}

header {
  background: var(--background-color);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  padding: 1.5rem 1rem;
  gap: 1rem;
}

.profile-photo {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
  border: 3px solid var(--primary-color);
}

.profile-photo img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.site-title {
  flex: 1;
}

.site-title h1 {
  margin: 0;
  font-size: 1.8rem;
  font-weight: 500;
}

.site-title p {
  margin: 0.2rem 0 0;
  color: var(--muted-color);
}

nav {
  background: var(--background-color);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  gap: 1rem;
  padding: 0.5rem 1rem;
}

.nav-inner a {
  padding: 0.5rem 0.75rem;
  border-radius: 999px;
  font-weight: 500;
  color: var(--muted-color);
}

.nav-inner a.active,
.nav-inner a:hover,
.nav-inner a:focus {
  color: var(--primary-color);
  background: rgba(26, 115, 232, 0.1);
  text-decoration: none;
}

main {
  max-width: 1100px;
  margin: 2rem auto;
  padding: 0 1rem 4rem;
}

.section-card {
  background: var(--card-background);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.section-card h2 {
  margin-top: 0;
  font-weight: 500;
}

.section-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.table-wrapper {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

thead th {
  text-align: left;
  font-weight: 500;
  color: var(--muted-color);
  font-size: 0.9rem;
  border-bottom: 1px solid var(--border-color);
  padding: 0.5rem;
}

tbody td {
  padding: 0.75rem 0.5rem;
  border-bottom: 1px solid var(--border-color);
  vertical-align: top;
}

.publication-title {
  font-weight: 500;
  color: var(--primary-color);
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}

.metric-card {
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background: var(--background-color);
}

.metric-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
}

.metric-card p {
  margin: 0.2rem 0;
  color: var(--muted-color);
}

footer {
  background: var(--card-background);
  border-top: 1px solid var(--border-color);
  padding: 1.5rem 1rem;
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  align-items: center;
  justify-content: space-between;
}

.footer-links {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.footer-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--muted-color);
}

.contact-icon {
  width: 20px;
  height: 20px;
  fill: var(--muted-color);
}

.qr-wrapper {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.badge {
  display: inline-block;
  background: rgba(26, 115, 232, 0.12);
  color: var(--primary-color);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.85rem;
  margin-right: 0.5rem;
}

.profile-meta {
  color: var(--muted-color);
  margin: 0.5rem 0 1rem;
}

.profile-meta span {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-right: 1rem;
}

.chart-container {
  background: var(--background-color);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
}

.bio-section p {
  margin-top: 0;
  font-size: 1.05rem;
}

.two-column {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.button {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-weight: 500;
  background: var(--primary-color);
  color: white;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.button:hover,
.button:focus {
  text-decoration: none;
  transform: translateY(-1px);
  box-shadow: 0 8px 16px rgba(26, 115, 232, 0.25);
}

@media (max-width: 720px) {
  .header-inner {
    flex-direction: column;
    text-align: center;
  }

  .profile-photo {
    margin-bottom: 0.5rem;
  }

  .site-title h1 {
    font-size: 1.5rem;
  }

  .nav-inner {
    flex-wrap: wrap;
    justify-content: center;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}