:root {
  --text: #222;
  --muted: #555;
  --accent: #4a90d9;
  --pill-bg: #2b2b2b;
  --pill-fg: #fff;
  --max-width: 900px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: #fff;
}

.hero {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 64px 24px 32px;
  text-align: center;
}

.title {
  font-size: 2.75rem;
  margin: 0 0 16px;
  font-weight: 700;
}

.emoji {
  margin-right: 8px;
}

.subtitle {
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--text);
  margin: 0 auto 24px;
  max-width: 720px;
}

.authors {
  color: var(--accent);
  font-size: 1.2rem;
  margin: 0 0 8px;
}

.affiliations {
  color: var(--muted);
  font-size: 1rem;
  margin: 0 0 4px;
}

.correspondence {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 0 0 32px;
}

.links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--pill-bg);
  color: var(--pill-fg);
  text-decoration: none;
  padding: 10px 20px;
  border-radius: 999px;
  font-size: 1rem;
  transition: opacity 0.15s ease;
}

.btn:hover {
  opacity: 0.8;
}

.btn-disabled {
  opacity: 0.6;
  cursor: default;
}

.btn-disabled em {
  font-style: italic;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px 64px;
}

.visual {
  text-align: center;
  margin: 24px 0 56px;
}

.visual img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
}

.content h2 {
  font-size: 2rem;
  text-align: center;
  margin-bottom: 24px;
}

.content p {
  color: var(--muted);
  font-size: 1.05rem;
  text-align: justify;
}

footer {
  text-align: center;
  padding: 24px;
  color: var(--muted);
  font-size: 0.9rem;
  border-top: 1px solid #eee;
}