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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #f8f9fa;
  color: #333;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2rem 1rem;
}

.container {
  max-width: 900px;
  width: 100%;
}

header {
  text-align: center;
  margin-bottom: 1.5rem;
}

header h1 {
  font-size: 2rem;
  font-weight: 700;
  color: #1a1a1a;
}

header .title {
  font-size: 1.1rem;
  color: #666;
  margin-bottom: 1rem;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.social-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: #555;
  text-decoration: none;
  font-size: 0.9rem;
  padding: 0.4rem 0.8rem;
  border: 1px solid #ddd;
  border-radius: 6px;
  transition: all 0.2s;
}

.social-links a:hover {
  background: #fff;
  border-color: #999;
  color: #1a1a1a;
}

.tabs {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.tab-btn {
  padding: 0.6rem 1.8rem;
  border: 2px solid #ddd;
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  transition: all 0.2s;
  color: #666;
}

.tab-btn:hover {
  border-color: #aaa;
  color: #333;
}

.tab-btn.active {
  border-color: #DC3522;
  color: #DC3522;
  background: #fde8e5;
}

.viewer-wrapper {
  background: #fff;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 1rem;
}

#pdf-viewer {
  width: 100%;
  height: 85vh;
  border: none;
  display: block;
}

.download-section {
  text-align: center;
  margin-bottom: 2rem;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 2rem;
  background: #DC3522;
  color: #fff;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  transition: background 0.2s;
}

.download-btn:hover {
  background: #b82a1b;
}

footer {
  text-align: center;
  color: #999;
  font-size: 0.8rem;
}

footer a {
  color: #666;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

@media (max-width: 768px) {
  body { padding: 1rem; }
  header h1 { font-size: 1.5rem; }
  #pdf-viewer { height: 60vh; }
  .tab-btn { padding: 0.5rem 1.2rem; font-size: 0.9rem; }
}