diff --git a/courses/223015b/slides/01-grundlagen.md b/courses/223015b/slides/01-grundlagen.md
index aa0b995..40da4dc 100644
--- a/courses/223015b/slides/01-grundlagen.md
+++ b/courses/223015b/slides/01-grundlagen.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/02-bild-audio-video.md b/courses/223015b/slides/02-bild-audio-video.md
index 9fac395..7c04eaf 100644
--- a/courses/223015b/slides/02-bild-audio-video.md
+++ b/courses/223015b/slides/02-bild-audio-video.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 </style>
 
 <!-- _class: invert -->
diff --git a/courses/223015b/slides/2025-12-19-termin-0-intro.md b/courses/223015b/slides/2025-12-19-termin-0-intro.md
index 1f17f3d..5dae55d 100644
--- a/courses/223015b/slides/2025-12-19-termin-0-intro.md
+++ b/courses/223015b/slides/2025-12-19-termin-0-intro.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/2025-12-19-termin-1-grundlagen-text-audio.md b/courses/223015b/slides/2025-12-19-termin-1-grundlagen-text-audio.md
index 60747b2..b5b1d0d 100644
--- a/courses/223015b/slides/2025-12-19-termin-1-grundlagen-text-audio.md
+++ b/courses/223015b/slides/2025-12-19-termin-1-grundlagen-text-audio.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/2026-01-09-termin-2-bild-audio-video.md b/courses/223015b/slides/2026-01-09-termin-2-bild-audio-video.md
index bd72471..0d32c0b 100644
--- a/courses/223015b/slides/2026-01-09-termin-2-bild-audio-video.md
+++ b/courses/223015b/slides/2026-01-09-termin-2-bild-audio-video.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/2026-01-23-termin-3-speichermedien-schnittstellen.md b/courses/223015b/slides/2026-01-23-termin-3-speichermedien-schnittstellen.md
index 2670a76..86ca325 100644
--- a/courses/223015b/slides/2026-01-23-termin-3-speichermedien-schnittstellen.md
+++ b/courses/223015b/slides/2026-01-23-termin-3-speichermedien-schnittstellen.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/2026-01-30-termin-4-distribution-apis-zukunft.md b/courses/223015b/slides/2026-01-30-termin-4-distribution-apis-zukunft.md
index 5cba704..0f60f8f 100644
--- a/courses/223015b/slides/2026-01-30-termin-4-distribution-apis-zukunft.md
+++ b/courses/223015b/slides/2026-01-30-termin-4-distribution-apis-zukunft.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/2026-xx-xx-termin-5-vertiefung-offene-fragen.md b/courses/223015b/slides/2026-xx-xx-termin-5-vertiefung-offene-fragen.md
index 82bfbcb..cb9cf9c 100644
--- a/courses/223015b/slides/2026-xx-xx-termin-5-vertiefung-offene-fragen.md
+++ b/courses/223015b/slides/2026-xx-xx-termin-5-vertiefung-offene-fragen.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #e3f2fd !important;
+  }
+}
 section.aufgabe {
   background: #e3f2fd !important;
 }
diff --git a/courses/223015b/slides/assets/quantized-image-8-colors.jpg b/courses/223015b/slides/assets/quantized-image-8-colors.jpg
new file mode 100644
index 0000000..6b4f39a
Binary files /dev/null and b/courses/223015b/slides/assets/quantized-image-8-colors.jpg differ
diff --git a/courses/223015c/slides/2025-12-20-termin-1-geschichte-grundlagen-html.md b/courses/223015c/slides/2025-12-20-termin-1-geschichte-grundlagen-html.md
index d7d201e..3a15ae2 100644
--- a/courses/223015c/slides/2025-12-20-termin-1-geschichte-grundlagen-html.md
+++ b/courses/223015c/slides/2025-12-20-termin-1-geschichte-grundlagen-html.md
@@ -55,7 +55,12 @@ section.klausur {
     #fce4ec 40px,
     #fff 40px,
     #fff 80px
-  );
+  ) !important;
+}
+@media print {
+  section.klausur {
+    background: #fce4ec !important;
+  }
 }
 section.aufgabe {
   background: #fce4ec !important;
diff --git a/courses/223015c/slides/2026-01-10-termin-2-netzwerke-protokolle-css.md b/courses/223015c/slides/2026-01-10-termin-2-netzwerke-protokolle-css.md
index ae7e01b..e221be7 100644
--- a/courses/223015c/slides/2026-01-10-termin-2-netzwerke-protokolle-css.md
+++ b/courses/223015c/slides/2026-01-10-termin-2-netzwerke-protokolle-css.md
@@ -57,6 +57,11 @@ section.klausur {
     #fff 80px
   ) !important;
 }
+@media print {
+  section.klausur {
+    background: #fce4ec !important;
+  }
+}
 section.aufgabe {
   background: #fce4ec !important;
 }
diff --git a/courses/223015c/slides/2026-01-24-termin-3-interaktivitaet-javascript.md b/courses/223015c/slides/2026-01-24-termin-3-interaktivitaet-javascript.md
index e3562bc..a7d69a6 100644
--- a/courses/223015c/slides/2026-01-24-termin-3-interaktivitaet-javascript.md
+++ b/courses/223015c/slides/2026-01-24-termin-3-interaktivitaet-javascript.md
@@ -55,7 +55,12 @@ section.klausur {
     #fce4ec 40px,
     #fff 40px,
     #fff 80px
-  );
+  ) !important;
+}
+@media print {
+  section.klausur {
+    background: #fce4ec !important;
+  }
 }
 section.aufgabe {
   background: #fce4ec !important;