branch-coexist: 3 neue decks 223015b-2026 / 223015c-2026 / dhbw-2026 daneben main

per user-request einen branch der main-content UND rewrite-content trägt — saubere separierung statt symlink/merge-conflict.

struktur:
- slides/<course>/ → main-content restored, eigene assets (kein new-demo-leak)
- slides/<course>-2026/ → rewrite-content, eigene assets (komplett kopiert + new demos)

Makefile: COURSES += 223015b-2026 223015c-2026 dhbw-2026 mit eigenen NAME/KAPITEL/DEPLOY/KLAUSUR-konfig. Klausur für b+c=1, dhbw=leer. Deploy-paths /hdm/223015b-2026 etc.

make build durchlaufen für alle 6 decks, 0 fehler.

dedup: 223015c+dhbw assets identisch in beiden ordnern (kein neu-demos auf b ergänzt). 223015b 86 → 120 files in -2026 (= +34 neue eroeffner/usb-c-drei-achsen/container-vs-codec/etc).

slides/223015c-2026/assets/demos/css-responsive.html

@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<html lang="de">
+<head>
+  <meta charset="UTF-8">
+  <title>Responsive Design – 3 Viewports</title>
+  <style>
+    html, body { margin: 0; padding: 0; font-family: system-ui, sans-serif; background: #fff; }
+    body { padding: 1rem; }
+    .viewport {
+      margin-bottom: 12px;
+      border: 1px solid #9ca3af;
+      border-radius: 4px;
+      overflow: hidden;
+    }
+    .bar {
+      background: #e5e7eb;
+      padding: 4px 10px;
+      font-size: 11px;
+      color: #374151;
+      font-family: ui-monospace, monospace;
+      border-bottom: 1px solid #9ca3af;
+    }
+    iframe { display: block; width: 100%; border: 0; }
+    .vp-mobile iframe { width: 360px; }
+    .vp-tablet iframe { width: 800px; }
+    .vp-desktop iframe { width: 1100px; }
+    .vp-mobile { width: 362px; }
+    .scroll { overflow: hidden; }
+  </style>
+</head>
+<body>
+  <div class="viewport vp-mobile">
+    <div class="bar">Mobile @ 360px</div>
+    <div class="scroll"><iframe src="./css-responsive-container.html" height="80"></iframe></div>
+  </div>
+  <div class="viewport vp-tablet">
+    <div class="bar">Tablet @ 800px</div>
+    <div class="scroll" style="overflow-x: auto;"><iframe src="./css-responsive-container.html" height="100"></iframe></div>
+  </div>
+  <div class="viewport vp-desktop">
+    <div class="bar">Desktop @ 1100px</div>
+    <div class="scroll" style="overflow-x: auto;"><iframe src="./css-responsive-container.html" height="100"></iframe></div>
+  </div>
+</body>
+</html>