body {
  font-family: Arial, sans-serif;
  background: #f5f5f5;
  padding: 20px;
  text-align: center;
}

.container {
  max-width: 600px;
  margin: auto;
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

h1 {
  font-size: 24px;
  margin-bottom: 16px;
}

input[type="file"] {
  margin: 12px 0;
}

#preview {
  margin-top: 16px;
  text-align: left;
  background: #272822;
  color: #f8f8f2;
  padding: 12px;
  border-radius: 4px;
  overflow: auto;
  max-height: 300px;
  font-family: monospace;
  display: none;
}

button {
  margin-top: 12px;
  padding: 10px 20px;
  font-size: 16px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  background-color: #007bff;
  color: #fff;
}

button:disabled {
  background-color: #999;
  cursor: not-allowed;
}

footer {
  margin-top: 40px;
  font-size: 14px;
  color: #666;
}

footer a.doc-link {
  display: inline-block;
  margin-top: 8px;
  color: #007bff;
  text-decoration: none;
  font-weight: bold;
  transition: color 0.2s ease;
}

footer a.doc-link:hover {
  color: #0056b3;
  text-decoration: underline;
}