body {
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  background-color: #ffffff;
  color: #222;
  margin: 0;
  padding: 0;
  line-height: 1.6;
}

header {
  text-align: center;
  padding: 60px 20px 40px 20px;
}

h1 {
  font-size: 2.4em;
  margin-bottom: 10px;
}

.authors, .affiliations {
  font-size: 1em;
  color: #555;
}

.links {
  margin-top: 15px;
}

.button {
  background: #222;
  color: #fff;
  padding: 8px 14px;
  text-decoration: none;
  border-radius: 5px;
  margin: 0 6px;
  transition: background 0.3s ease;
}

.button:hover {
  background: #444;
}

section {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

h2 {
  border-bottom: 2px solid #eee;
  padding-bottom: 6px;
  margin-bottom: 20px;
}

.placeholder {
  display: block;
  margin: 20px auto;
  max-width: 100%;
  border: 1px solid #ddd;
  border-radius: 6px;
}

pre {
  background-color: #f5f5f5;
  padding: 12px;
  border-radius: 6px;
  overflow-x: auto;
}

footer {
  text-align: center;
  font-size: 0.9em;
  color: #777;
  padding: 20px;
  border-top: 1px solid #eee;
}