diff --git a/slides/223015b/assets/demos/drei-dateien.html b/slides/223015b/assets/demos/drei-dateien.html
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+<!DOCTYPE html>
+<html lang="de">
+<head>
+<meta charset="UTF-8">
+<title>Drei Dateien — dasselbe Innenleben</title>
+<style>
+  :root {
+    --dark: #1a1a2e;
+    --muted: #6b7280;
+    --soft: #f8fafc;
+    --border: #cbd5e1;
+    --hl: #d63384;
+    --foto: #2563eb;
+    --audio: #ea580c;
+    --pdf: #7c3aed;
+  }
+  html, body { margin: 0; padding: 0; background: #fff; font-family: system-ui, -apple-system, sans-serif; color: var(--dark); }
+  body { padding: 32px 40px; }
+  h1 { text-align: center; margin: 0 0 6px; font-size: 1.85rem; }
+  .sub { text-align: center; color: var(--muted); margin-bottom: 28px; font-size: 1.05rem; }
+  .sub strong { color: var(--dark); }
+
+  .files {
+    display: grid;
+    grid-template-columns: 1fr 1fr 1fr;
+    gap: 22px;
+    max-width: 1200px;
+    margin: 0 auto;
+  }
+
+  .file {
+    border: 2px solid;
+    border-radius: 12px;
+    padding: 16px 18px;
+    background: #fff;
+    display: flex;
+    flex-direction: column;
+    gap: 12px;
+  }
+  .file.foto  { border-color: var(--foto); }
+  .file.audio { border-color: var(--audio); }
+  .file.pdf   { border-color: var(--pdf); }
+
+  .file-head { display: flex; justify-content: space-between; align-items: baseline; }
+  .file-name { font-size: 1.2rem; font-weight: 700; }
+  .file.foto  .file-name { color: var(--foto); }
+  .file.audio .file-name { color: var(--audio); }
+  .file.pdf   .file-name { color: var(--pdf); }
+  .file-ext { font-family: ui-monospace, monospace; font-size: 0.78rem; color: var(--muted); }
+
+  .preview {
+    border-radius: 8px;
+    border: 1px solid var(--border);
+    overflow: hidden;
+    display: block;
+    height: 130px;
+    background: var(--soft);
+  }
+
+  .hex-strip {
+    background: #0f0f23;
+    border-radius: 6px;
+    padding: 8px 10px;
+    font-family: ui-monospace, monospace;
+    font-size: 0.78rem;
+    line-height: 1.6;
+    color: #cbd5e1;
+    overflow: hidden;
+  }
+  .hex-strip .magic { color: #fff; font-weight: 700; padding: 0 2px; border-radius: 2px; }
+  .hex-strip.foto-magic .magic  { background: var(--foto); }
+  .hex-strip.audio-magic .magic { background: var(--audio); }
+  .hex-strip.pdf-magic .magic   { background: var(--pdf); }
+  .hex-label {
+    font-size: 0.68rem;
+    text-transform: uppercase;
+    letter-spacing: 0.1em;
+    color: var(--muted);
+    font-weight: 700;
+    margin-bottom: 2px;
+  }
+  .magic-caption {
+    font-size: 0.78rem;
+    color: var(--muted);
+    text-align: center;
+    font-family: ui-monospace, monospace;
+  }
+  .magic-caption .magic-word {
+    color: var(--dark);
+    font-weight: 700;
+  }
+
+  .verdict {
+    margin-top: 26px;
+    max-width: 1200px;
+    margin-left: auto;
+    margin-right: auto;
+    text-align: center;
+    border: 2px solid var(--hl);
+    border-radius: 12px;
+    padding: 14px 22px;
+  }
+  .verdict-q { font-size: 1.15rem; font-weight: 700; color: var(--hl); }
+  .verdict-a { font-size: 0.95rem; color: var(--dark); margin-top: 4px; }
+  .verdict-a strong { color: var(--hl); }
+</style>
+</head>
+<body>
+  <h1>Drei Dateien — dasselbe Innenleben</h1>
+  <div class="sub">Außen <strong>völlig verschieden</strong>. Innen reden alle dieselbe Sprache: <strong>Byte für Byte</strong>.</div>
+
+  <div class="files">
+
+    <div class="file foto">
+      <div class="file-head">
+        <span class="file-name">Foto</span>
+        <span class="file-ext">.png</span>
+      </div>
+      <svg class="preview" viewBox="0 0 220 130" preserveAspectRatio="xMidYMid slice">
+        <defs>
+          <linearGradient id="sky-f" x1="0" y1="0" x2="0" y2="1">
+            <stop offset="0%" stop-color="#fde68a"/>
+            <stop offset="60%" stop-color="#fb923c"/>
+            <stop offset="100%" stop-color="#7c3aed"/>
+          </linearGradient>
+        </defs>
+        <rect x="0" y="0" width="220" height="130" fill="url(#sky-f)"/>
+        <circle cx="160" cy="50" r="18" fill="#fef3c7" opacity="0.95"/>
+        <path d="M0,95 L40,80 L80,90 L120,72 L160,86 L220,75 L220,130 L0,130 Z" fill="#1e1b4b"/>
+        <path d="M0,110 L60,100 L120,108 L180,98 L220,105 L220,130 L0,130 Z" fill="#0f172a" opacity="0.7"/>
+      </svg>
+      <div>
+        <div class="hex-label">Erste Bytes der Datei</div>
+        <div class="hex-strip foto-magic">
+<span class="magic">89 50 4E 47</span> 0D 0A 1A 0A 00 00 00 0D 49 48 44 52
+        </div>
+      </div>
+      <div class="magic-caption"><span class="magic-word">50 4E 47</span> = <span class="magic-word">"PNG"</span></div>
+    </div>
+
+    <div class="file audio">
+      <div class="file-head">
+        <span class="file-name">Sprachnachricht</span>
+        <span class="file-ext">.mp3</span>
+      </div>
+      <svg class="preview" viewBox="0 0 220 130" preserveAspectRatio="none">
+        <rect x="0" y="0" width="220" height="130" fill="#0f0f23"/>
+        <line x1="0" y1="65" x2="220" y2="65" stroke="#374151" stroke-width="1"/>
+        <path d="M0,65 L8,65 L12,55 L16,75 L20,40 L24,90 L28,30 L32,95 L36,35 L40,90
+          L48,45 L56,82 L64,50 L72,78 L80,52 L88,75 L96,55 L104,72
+          L116,58 L128,72 L140,60 L152,70 L168,62 L184,68 L200,64 L220,65
+          L220,130 L0,130 Z" fill="#fb923c" stroke="#ea580c" stroke-width="1"/>
+      </svg>
+      <div>
+        <div class="hex-label">Erste Bytes der Datei</div>
+        <div class="hex-strip audio-magic">
+<span class="magic">49 44 33</span> 03 00 00 00 00 03 76 54 49 54 32 00 00
+        </div>
+      </div>
+      <div class="magic-caption"><span class="magic-word">49 44 33</span> = <span class="magic-word">"ID3"</span></div>
+    </div>
+
+    <div class="file pdf">
+      <div class="file-head">
+        <span class="file-name">PDF-Dokument</span>
+        <span class="file-ext">.pdf</span>
+      </div>
+      <svg class="preview" viewBox="0 0 220 130" preserveAspectRatio="xMidYMid meet">
+        <rect x="0" y="0" width="220" height="130" fill="#f8fafc"/>
+        <rect x="50" y="14" width="120" height="102" rx="4" fill="#fff" stroke="#cbd5e1" stroke-width="1"/>
+        <rect x="58" y="24" width="80" height="4" rx="1" fill="#7c3aed"/>
+        <rect x="58" y="34" width="104" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="40" width="98" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="46" width="92" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="52" width="100" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="62" width="80" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="68" width="96" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="74" width="88" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="84" width="40" height="3" rx="1" fill="#7c3aed" opacity="0.7"/>
+        <rect x="58" y="92" width="92" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="98" width="86" height="2" fill="#cbd5e1"/>
+        <rect x="58" y="104" width="78" height="2" fill="#cbd5e1"/>
+      </svg>
+      <div>
+        <div class="hex-label">Erste Bytes der Datei</div>
+        <div class="hex-strip pdf-magic">
+<span class="magic">25 50 44 46</span> 2D 31 2E 37 0A 25 E2 E3 CF D3 0A 0A
+        </div>
+      </div>
+      <div class="magic-caption"><span class="magic-word">25 50 44 46</span> = <span class="magic-word">"%PDF"</span></div>
+    </div>
+
+  </div>
+
+  <div class="verdict">
+    <div class="verdict-q">Drei verschiedene Dinge — eine Sprache.</div>
+    <div class="verdict-a">Jede Datei beginnt mit ihrer <strong>Visitenkarte</strong> (Magic Number) und besteht ab da aus nichts als Byte. Foto, Audio, PDF — alle dieselben Bauteile, nur anders zusammengesetzt.</div>
+  </div>
+</body>
+</html>
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