 URL or local PDF -->
    <div class="flex justify-center mb-4">
      <select id="pdfSource" class="px-4 py-2 border border-gray-400 rounded-lg bg-white text-black w-full">
        <option value="local">Local PDF</option>
        <option value="url" selected>URL PDF</option>
      </select>
    </div>

    <!-- Input field for the PDF URL -->
    <div id="urlInputField" class="flex justify-center mb-4">
      <input id="pdfUrl" type="text" placeholder="Enter PDF URL" 
             class="px-4 py-2 border b