Restructure upload flow: document first, then preview + naming

Step 1 is now document selection (full width).
After selecting a file, Step 2 shows a side-by-side layout with
document preview (3/5 width, scrollable, with fullscreen modal)
and session naming (2/5 width, with start button).

Also adds PDF preview via blob URL before upload.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

studio-v2/app/vocab-worksheet/page.tsx

@@ -130,6 +130,7 @@ export default function VocabWorksheetPage() {
   // Direct file upload
   const [directFile, setDirectFile] = useState<File | null>(null)
   const [directFilePreview, setDirectFilePreview] = useState<string | null>(null)
+  const [showFullPreview, setShowFullPreview] = useState(false)
   const directFileInputRef = useRef<HTMLInputElement>(null)
 
   // PDF page selection state
@@ -263,6 +264,7 @@ export default function VocabWorksheetPage() {
 
     setDirectFile(file)
     setSelectedDocumentId(null)
+    setSelectedMobileFile(null)
 
     if (file.type.startsWith('image/')) {
       const reader = new FileReader()
@@ -270,6 +272,8 @@ export default function VocabWorksheetPage() {
         setDirectFilePreview(ev.target?.result as string)
       }
       reader.readAsDataURL(file)
+    } else if (file.type === 'application/pdf') {
+      setDirectFilePreview(URL.createObjectURL(file))
     } else {
       setDirectFilePreview(null)
     }
@@ -826,6 +830,7 @@ export default function VocabWorksheetPage() {
     setSelectedDocumentId(null)
     setDirectFile(null)
     setDirectFilePreview(null)
+    setShowFullPreview(false)
     setPdfPageCount(0)
     setSelectedPages([])
     setPagesThumbnails([])
@@ -1219,19 +1224,19 @@ export default function VocabWorksheetPage() {
               <ol className={`space-y-2 ${isDark ? 'text-white/70' : 'text-slate-600'}`}>
                 <li className="flex items-start gap-2">
                   <span className={`w-6 h-6 rounded-full flex items-center justify-center text-xs font-bold flex-shrink-0 ${isDark ? 'bg-purple-500/30 text-purple-300' : 'bg-purple-200 text-purple-700'}`}>1</span>
-                  <span>Session benennen und Dokument (Bild oder PDF) auswaehlen</span>
+                  <span>Dokument (Bild oder PDF) auswaehlen</span>
                 </li>
                 <li className="flex items-start gap-2">
                   <span className={`w-6 h-6 rounded-full flex items-center justify-center text-xs font-bold flex-shrink-0 ${isDark ? 'bg-purple-500/30 text-purple-300' : 'bg-purple-200 text-purple-700'}`}>2</span>
-                  <span>Bei PDFs: Seiten auswaehlen die verarbeitet werden sollen</span>
+                  <span>Vorschau pruefen und Session benennen</span>
                 </li>
                 <li className="flex items-start gap-2">
                   <span className={`w-6 h-6 rounded-full flex items-center justify-center text-xs font-bold flex-shrink-0 ${isDark ? 'bg-purple-500/30 text-purple-300' : 'bg-purple-200 text-purple-700'}`}>3</span>
-                  <span>KI extrahiert automatisch Vokabeln (Englisch | Deutsch | Beispiel)</span>
+                  <span>Bei PDFs: Seiten auswaehlen die verarbeitet werden sollen</span>
                 </li>
                 <li className="flex items-start gap-2">
                   <span className={`w-6 h-6 rounded-full flex items-center justify-center text-xs font-bold flex-shrink-0 ${isDark ? 'bg-purple-500/30 text-purple-300' : 'bg-purple-200 text-purple-700'}`}>4</span>
-                  <span>Vokabeln pruefen/korrigieren und Arbeitsblatt-Typ waehlen</span>
+                  <span>KI extrahiert Vokabeln — pruefen, korrigieren, Arbeitsblatt-Typ waehlen</span>
                 </li>
                 <li className="flex items-start gap-2">
                   <span className={`w-6 h-6 rounded-full flex items-center justify-center text-xs font-bold flex-shrink-0 ${isDark ? 'bg-purple-500/30 text-purple-300' : 'bg-purple-200 text-purple-700'}`}>5</span>
@@ -1240,174 +1245,215 @@ export default function VocabWorksheetPage() {
               </ol>
             </div>
 
-            {/* Two Column Layout */}
-            <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
-              {/* Session Name */}
-              <div className={`${glassCard} rounded-2xl p-6`}>
-                <h2 className={`text-lg font-semibold mb-4 ${isDark ? 'text-white' : 'text-slate-900'}`}>
-                  1. Session benennen
-                </h2>
-                <input
-                  type="text"
-                  value={sessionName}
-                  onChange={(e) => { setSessionName(e.target.value); setError(null) }}
-                  placeholder="z.B. Englisch Klasse 7 - Unit 3"
-                  className={`w-full px-4 py-3 rounded-xl border ${glassInput} focus:outline-none focus:ring-2 focus:ring-purple-500`}
-                />
+            {/* Step 1: Document Selection */}
+            <div className={`${glassCard} rounded-2xl p-6`}>
+              <h2 className={`text-lg font-semibold mb-4 ${isDark ? 'text-white' : 'text-slate-900'}`}>
+                1. Dokument auswaehlen
+              </h2>
+
+              <input ref={directFileInputRef} type="file" accept="image/png,image/jpeg,image/jpg,application/pdf" onChange={handleDirectFileSelect} className="hidden" />
+
+              <div className="grid grid-cols-2 gap-3 mb-4">
+                {/* File Upload Button */}
+                <button
+                  onClick={() => directFileInputRef.current?.click()}
+                  className={`p-4 rounded-xl border-2 border-dashed transition-all ${
+                    directFile
+                      ? (isDark ? 'border-green-400/50 bg-green-500/20' : 'border-green-500 bg-green-50')
+                      : (isDark ? 'border-white/20 hover:border-purple-400/50' : 'border-slate-300 hover:border-purple-500')
+                  }`}
+                >
+                  {directFile ? (
+                    <div className="flex items-center gap-3">
+                      <span className="text-2xl">{directFile.type === 'application/pdf' ? '📄' : '🖼️'}</span>
+                      <div className="text-left flex-1 min-w-0">
+                        <p className={`font-medium truncate ${isDark ? 'text-white' : 'text-slate-900'}`}>{directFile.name}</p>
+                        <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>{formatFileSize(directFile.size)}</p>
+                      </div>
+                      <svg className="w-5 h-5 text-green-500 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
+                      </svg>
+                    </div>
+                  ) : (
+                    <div className={`text-center ${isDark ? 'text-white/60' : 'text-slate-500'}`}>
+                      <span className="text-2xl block mb-1">📁</span>
+                      <span className="text-sm">Datei auswaehlen</span>
+                    </div>
+                  )}
+                </button>
+
+                {/* QR Code Upload Button */}
+                <button
+                  onClick={() => setShowQRModal(true)}
+                  className={`p-4 rounded-xl border-2 border-dashed transition-all ${
+                    selectedMobileFile
+                      ? (isDark ? 'border-green-400/50 bg-green-500/20' : 'border-green-500 bg-green-50')
+                      : (isDark ? 'border-white/20 hover:border-purple-400/50' : 'border-slate-300 hover:border-purple-500')
+                  }`}
+                >
+                  {selectedMobileFile ? (
+                    <div className="flex items-center gap-3">
+                      <span className="text-2xl">{selectedMobileFile.type.startsWith('image/') ? '🖼️' : '📄'}</span>
+                      <div className="text-left flex-1 min-w-0">
+                        <p className={`font-medium truncate text-sm ${isDark ? 'text-white' : 'text-slate-900'}`}>{selectedMobileFile.name}</p>
+                        <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>vom Handy</p>
+                      </div>
+                      <svg className="w-5 h-5 text-green-500 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
+                      </svg>
+                    </div>
+                  ) : (
+                    <div className={`text-center ${isDark ? 'text-white/60' : 'text-slate-500'}`}>
+                      <span className="text-2xl block mb-1">📱</span>
+                      <span className="text-sm">Mit Handy scannen</span>
+                    </div>
+                  )}
+                </button>
               </div>
 
-              {/* Document Selection */}
-              <div className={`${glassCard} rounded-2xl p-6`}>
-                <h2 className={`text-lg font-semibold mb-4 ${isDark ? 'text-white' : 'text-slate-900'}`}>
-                  2. Dokument auswaehlen
-                </h2>
-
-                {/* Direct Upload */}
-                <input ref={directFileInputRef} type="file" accept="image/png,image/jpeg,image/jpg,application/pdf" onChange={handleDirectFileSelect} className="hidden" />
-
-                {/* Two upload options side by side */}
-                <div className="grid grid-cols-2 gap-3 mb-4">
-                  {/* File Upload Button */}
-                  <button
-                    onClick={() => directFileInputRef.current?.click()}
-                    className={`p-4 rounded-xl border-2 border-dashed transition-all ${
-                      directFile
-                        ? (isDark ? 'border-green-400/50 bg-green-500/20' : 'border-green-500 bg-green-50')
-                        : (isDark ? 'border-white/20 hover:border-purple-400/50' : 'border-slate-300 hover:border-purple-500')
-                    }`}
-                  >
-                    {directFile ? (
-                      <div className="flex items-center gap-3">
-                        <span className="text-2xl">{directFile.type === 'application/pdf' ? '📄' : '🖼️'}</span>
-                        <div className="text-left flex-1 min-w-0">
-                          <p className={`font-medium truncate ${isDark ? 'text-white' : 'text-slate-900'}`}>{directFile.name}</p>
-                          <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>{formatFileSize(directFile.size)}</p>
+              {/* Mobile Uploaded Files */}
+              {mobileUploadedFiles.length > 0 && !directFile && (
+                <>
+                  <div className={`text-center text-sm mb-3 ${isDark ? 'text-white/40' : 'text-slate-400'}`}>— Vom Handy hochgeladen —</div>
+                  <div className="space-y-2 max-h-32 overflow-y-auto mb-4">
+                    {mobileUploadedFiles.map((file) => (
+                      <button
+                        key={file.id}
+                        onClick={() => { setSelectedMobileFile(file); setDirectFile(null); setSelectedDocumentId(null); setError(null) }}
+                        className={`w-full flex items-center gap-3 p-3 rounded-xl text-left transition-all ${
+                          selectedMobileFile?.id === file.id
+                            ? (isDark ? 'bg-green-500/30 border-2 border-green-400/50' : 'bg-green-100 border-2 border-green-500')
+                            : (isDark ? 'bg-white/5 border-2 border-transparent hover:border-white/20' : 'bg-slate-50 border-2 border-transparent hover:border-slate-200')
+                        }`}
+                      >
+                        <span className="text-xl">{file.type.startsWith('image/') ? '🖼️' : '📄'}</span>
+                        <div className="flex-1 min-w-0">
+                          <p className={`font-medium truncate ${isDark ? 'text-white' : 'text-slate-900'}`}>{file.name}</p>
+                          <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>{formatFileSize(file.size)}</p>
                         </div>
-                        <svg className="w-5 h-5 text-green-500 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
-                        </svg>
-                      </div>
-                    ) : (
-                      <div className={`text-center ${isDark ? 'text-white/60' : 'text-slate-500'}`}>
-                        <span className="text-2xl block mb-1">📁</span>
-                        <span className="text-sm">Datei auswaehlen</span>
-                      </div>
-                    )}
-                  </button>
+                        {selectedMobileFile?.id === file.id && (
+                          <svg className="w-5 h-5 text-green-500" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
+                          </svg>
+                        )}
+                      </button>
+                    ))}
+                  </div>
+                </>
+              )}
 
-                  {/* QR Code Upload Button */}
-                  <button
-                    onClick={() => setShowQRModal(true)}
-                    className={`p-4 rounded-xl border-2 border-dashed transition-all ${
-                      selectedMobileFile
-                        ? (isDark ? 'border-green-400/50 bg-green-500/20' : 'border-green-500 bg-green-50')
-                        : (isDark ? 'border-white/20 hover:border-purple-400/50' : 'border-slate-300 hover:border-purple-500')
-                    }`}
-                  >
-                    {selectedMobileFile ? (
-                      <div className="flex items-center gap-3">
-                        <span className="text-2xl">{selectedMobileFile.type.startsWith('image/') ? '🖼️' : '📄'}</span>
-                        <div className="text-left flex-1 min-w-0">
-                          <p className={`font-medium truncate text-sm ${isDark ? 'text-white' : 'text-slate-900'}`}>{selectedMobileFile.name}</p>
-                          <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>vom Handy</p>
+              {/* Stored Documents */}
+              {storedDocuments.length > 0 && !directFile && !selectedMobileFile && (
+                <>
+                  <div className={`text-center text-sm mb-3 ${isDark ? 'text-white/40' : 'text-slate-400'}`}>— oder aus Ihren Dokumenten —</div>
+                  <div className="space-y-2 max-h-32 overflow-y-auto">
+                    {storedDocuments.map((doc) => (
+                      <button
+                        key={doc.id}
+                        onClick={() => { setSelectedDocumentId(doc.id); setDirectFile(null); setSelectedMobileFile(null); setError(null) }}
+                        className={`w-full flex items-center gap-3 p-3 rounded-xl text-left transition-all ${
+                          selectedDocumentId === doc.id
+                            ? (isDark ? 'bg-purple-500/30 border-2 border-purple-400/50' : 'bg-purple-100 border-2 border-purple-500')
+                            : (isDark ? 'bg-white/5 border-2 border-transparent hover:border-white/20' : 'bg-slate-50 border-2 border-transparent hover:border-slate-200')
+                        }`}
+                      >
+                        <span className="text-xl">{doc.type === 'application/pdf' ? '📄' : '🖼️'}</span>
+                        <div className="flex-1 min-w-0">
+                          <p className={`font-medium truncate ${isDark ? 'text-white' : 'text-slate-900'}`}>{doc.name}</p>
+                          <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>{formatFileSize(doc.size)}</p>
                         </div>
-                        <svg className="w-5 h-5 text-green-500 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
-                        </svg>
-                      </div>
-                    ) : (
-                      <div className={`text-center ${isDark ? 'text-white/60' : 'text-slate-500'}`}>
-                        <span className="text-2xl block mb-1">📱</span>
-                        <span className="text-sm">Mit Handy scannen</span>
-                      </div>
+                        {selectedDocumentId === doc.id && (
+                          <svg className="w-5 h-5 text-purple-500" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
+                          </svg>
+                        )}
+                      </button>
+                    ))}
+                  </div>
+                </>
+              )}
+            </div>
+
+            {/* Step 2: Preview + Session Name (shown when document selected) */}
+            {(directFile || selectedMobileFile || selectedDocumentId) && (
+              <div className="grid grid-cols-1 lg:grid-cols-5 gap-6">
+                {/* Document Preview */}
+                <div className={`${glassCard} rounded-2xl p-6 lg:col-span-3`}>
+                  <div className="flex items-center justify-between mb-4">
+                    <h2 className={`text-lg font-semibold ${isDark ? 'text-white' : 'text-slate-900'}`}>
+                      Vorschau
+                    </h2>
+                    <button
+                      onClick={() => setShowFullPreview(true)}
+                      className={`px-3 py-1.5 rounded-lg text-sm font-medium transition-all flex items-center gap-2 ${
+                        isDark ? 'bg-white/10 hover:bg-white/20 text-white' : 'bg-slate-100 hover:bg-slate-200 text-slate-700'
+                      }`}
+                    >
+                      <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M21 21l-6-6m2-5a7 7 0 11-14 0 7 7 0 0114 0zM10 7v3m0 0v3m0-3h3m-3 0H7" />
+                      </svg>
+                      Originalgroesse
+                    </button>
+                  </div>
+                  <div className={`max-h-[60vh] overflow-auto rounded-xl border ${isDark ? 'border-white/10' : 'border-black/10'}`}>
+                    {/* Image preview from file */}
+                    {directFile?.type.startsWith('image/') && directFilePreview && (
+                      <img src={directFilePreview} alt="Vorschau" className="w-full h-auto" />
                     )}
-                  </button>
+                    {/* PDF preview from file */}
+                    {directFile?.type === 'application/pdf' && directFilePreview && (
+                      <iframe src={directFilePreview} className="w-full border-0 rounded-xl" style={{ height: '60vh' }} />
+                    )}
+                    {/* Mobile file preview */}
+                    {selectedMobileFile && !directFile && (
+                      selectedMobileFile.type.startsWith('image/')
+                        ? <img src={selectedMobileFile.dataUrl} alt="Vorschau" className="w-full h-auto" />
+                        : <iframe src={selectedMobileFile.dataUrl} className="w-full border-0 rounded-xl" style={{ height: '60vh' }} />
+                    )}
+                    {/* Stored document preview */}
+                    {selectedDocumentId && !directFile && !selectedMobileFile && (() => {
+                      const doc = storedDocuments.find(d => d.id === selectedDocumentId)
+                      if (!doc?.url) return <p className={`p-8 text-center ${isDark ? 'text-white/40' : 'text-slate-400'}`}>Keine Vorschau verfuegbar</p>
+                      return doc.type.startsWith('image/')
+                        ? <img src={doc.url} alt="Vorschau" className="w-full h-auto" />
+                        : <iframe src={doc.url} className="w-full border-0 rounded-xl" style={{ height: '60vh' }} />
+                    })()}
+                  </div>
                 </div>
 
-                {/* Mobile Uploaded Files */}
-                {mobileUploadedFiles.length > 0 && !directFile && (
-                  <>
-                    <div className={`text-center text-sm mb-3 ${isDark ? 'text-white/40' : 'text-slate-400'}`}>— Vom Handy hochgeladen —</div>
-                    <div className="space-y-2 max-h-32 overflow-y-auto mb-4">
-                      {mobileUploadedFiles.map((file) => (
-                        <button
-                          key={file.id}
-                          onClick={() => { setSelectedMobileFile(file); setDirectFile(null); setSelectedDocumentId(null); setError(null) }}
-                          className={`w-full flex items-center gap-3 p-3 rounded-xl text-left transition-all ${
-                            selectedMobileFile?.id === file.id
-                              ? (isDark ? 'bg-green-500/30 border-2 border-green-400/50' : 'bg-green-100 border-2 border-green-500')
-                              : (isDark ? 'bg-white/5 border-2 border-transparent hover:border-white/20' : 'bg-slate-50 border-2 border-transparent hover:border-slate-200')
-                          }`}
-                        >
-                          <span className="text-xl">{file.type.startsWith('image/') ? '🖼️' : '📄'}</span>
-                          <div className="flex-1 min-w-0">
-                            <p className={`font-medium truncate ${isDark ? 'text-white' : 'text-slate-900'}`}>{file.name}</p>
-                            <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>{formatFileSize(file.size)}</p>
-                          </div>
-                          {selectedMobileFile?.id === file.id && (
-                            <svg className="w-5 h-5 text-green-500" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
-                            </svg>
-                          )}
-                        </button>
-                      ))}
-                    </div>
-                  </>
-                )}
-
-                {/* Stored Documents */}
-                {storedDocuments.length > 0 && !directFile && (
-                  <>
-                    <div className={`text-center text-sm mb-3 ${isDark ? 'text-white/40' : 'text-slate-400'}`}>— oder aus Ihren Dokumenten —</div>
-                    <div className="space-y-2 max-h-32 overflow-y-auto">
-                      {storedDocuments.map((doc) => (
-                        <button
-                          key={doc.id}
-                          onClick={() => { setSelectedDocumentId(doc.id); setDirectFile(null); setError(null) }}
-                          className={`w-full flex items-center gap-3 p-3 rounded-xl text-left transition-all ${
-                            selectedDocumentId === doc.id
-                              ? (isDark ? 'bg-purple-500/30 border-2 border-purple-400/50' : 'bg-purple-100 border-2 border-purple-500')
-                              : (isDark ? 'bg-white/5 border-2 border-transparent hover:border-white/20' : 'bg-slate-50 border-2 border-transparent hover:border-slate-200')
-                          }`}
-                        >
-                          <span className="text-xl">{doc.type === 'application/pdf' ? '📄' : '🖼️'}</span>
-                          <div className="flex-1 min-w-0">
-                            <p className={`font-medium truncate ${isDark ? 'text-white' : 'text-slate-900'}`}>{doc.name}</p>
-                            <p className={`text-xs ${isDark ? 'text-white/60' : 'text-slate-500'}`}>{formatFileSize(doc.size)}</p>
-                          </div>
-                          {selectedDocumentId === doc.id && (
-                            <svg className="w-5 h-5 text-purple-500" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
-                            </svg>
-                          )}
-                        </button>
-                      ))}
-                    </div>
-                  </>
-                )}
+                {/* Session Name + Start */}
+                <div className={`${glassCard} rounded-2xl p-6 lg:col-span-2 flex flex-col`}>
+                  <h2 className={`text-lg font-semibold mb-4 ${isDark ? 'text-white' : 'text-slate-900'}`}>
+                    2. Session benennen
+                  </h2>
+                  <input
+                    type="text"
+                    value={sessionName}
+                    onChange={(e) => { setSessionName(e.target.value); setError(null) }}
+                    placeholder="z.B. Englisch Klasse 7 - Unit 3"
+                    className={`w-full px-4 py-3 rounded-xl border ${glassInput} focus:outline-none focus:ring-2 focus:ring-purple-500 mb-4`}
+                    autoFocus
+                  />
+                  <p className={`text-sm mb-6 ${isDark ? 'text-white/50' : 'text-slate-500'}`}>
+                    Benennen Sie die Session z.B. nach dem Schulbuch-Kapitel, damit Sie sie spaeter wiederfinden.
+                  </p>
+                  <div className="flex-1" />
+                  <button
+                    onClick={() => {
+                      if (!sessionName.trim()) {
+                        setError('Bitte geben Sie einen Session-Namen ein (z.B. "Englisch Klasse 7 - Unit 3")')
+                        return
+                      }
+                      startSession()
+                    }}
+                    disabled={isCreatingSession || !sessionName.trim()}
+                    className="w-full px-6 py-4 bg-gradient-to-r from-purple-500 to-pink-500 text-white rounded-2xl font-semibold text-lg disabled:opacity-50 hover:shadow-xl hover:shadow-purple-500/30 transition-all transform hover:scale-105"
+                  >
+                    {isCreatingSession ? 'Verarbeite...' : 'Weiter →'}
+                  </button>
+                </div>
               </div>
-            </div>
-
-            {/* Start Button */}
-            <div className="flex justify-center">
-              <button
-                onClick={() => {
-                  if (!sessionName.trim()) {
-                    alert('Bitte geben Sie einen Session-Namen ein (z.B. "Englisch Klasse 7 - Unit 3")')
-                    return
-                  }
-                  if (!selectedDocumentId && !directFile && !selectedMobileFile) {
-                    alert('Bitte wählen Sie ein Dokument aus oder laden Sie eine Datei hoch.')
-                    return
-                  }
-                  startSession()
-                }}
-                disabled={isCreatingSession}
-                className="px-8 py-4 bg-gradient-to-r from-purple-500 to-pink-500 text-white rounded-2xl font-semibold text-lg disabled:opacity-50 hover:shadow-xl hover:shadow-purple-500/30 transition-all transform hover:scale-105"
-              >
-                {isCreatingSession ? 'Verarbeite...' : 'Weiter →'}
-              </button>
-            </div>
+            )}
           </div>
         )}
 
@@ -2019,6 +2065,40 @@ export default function VocabWorksheetPage() {
         )}
       </div>
 
+      {/* Fullscreen Preview Modal */}
+      {showFullPreview && (
+        <div className="fixed inset-0 z-50 bg-black/80 backdrop-blur-sm flex items-center justify-center" onClick={() => setShowFullPreview(false)}>
+          <button
+            onClick={() => setShowFullPreview(false)}
+            className="absolute top-4 right-4 p-2 rounded-full bg-white/10 hover:bg-white/20 text-white z-10 transition-colors"
+          >
+            <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
+            </svg>
+          </button>
+          <div className="max-w-[95vw] max-h-[95vh] overflow-auto" onClick={(e) => e.stopPropagation()}>
+            {directFile?.type.startsWith('image/') && directFilePreview && (
+              <img src={directFilePreview} alt="Original" className="max-w-none" />
+            )}
+            {directFile?.type === 'application/pdf' && directFilePreview && (
+              <iframe src={directFilePreview} className="border-0 rounded-xl bg-white" style={{ width: '90vw', height: '90vh' }} />
+            )}
+            {selectedMobileFile && !directFile && (
+              selectedMobileFile.type.startsWith('image/')
+                ? <img src={selectedMobileFile.dataUrl} alt="Original" className="max-w-none" />
+                : <iframe src={selectedMobileFile.dataUrl} className="border-0 rounded-xl bg-white" style={{ width: '90vw', height: '90vh' }} />
+            )}
+            {selectedDocumentId && !directFile && !selectedMobileFile && (() => {
+              const doc = storedDocuments.find(d => d.id === selectedDocumentId)
+              if (!doc?.url) return null
+              return doc.type.startsWith('image/')
+                ? <img src={doc.url} alt="Original" className="max-w-none" />
+                : <iframe src={doc.url} className="border-0 rounded-xl bg-white" style={{ width: '90vw', height: '90vh' }} />
+            })()}
+          </div>
+        </div>
+      )}
+
       {/* QR Code Modal */}
       {showQRModal && (
         <div className="fixed inset-0 z-50 flex items-center justify-center p-4">