diff --git a/slides/223015b/01-grundlagen-text-audio.md b/slides/223015b/01-grundlagen-text-audio.md
index fbad37b..153832d 100644
--- a/slides/223015b/01-grundlagen-text-audio.md
+++ b/slides/223015b/01-grundlagen-text-audio.md
@@ -75,11 +75,6 @@ section.erklaerung :not(footer)
 {
   font-size: 1.1rem;
 }
-@media print {
-  section.erklaerung {
-    background: #e3f2fd !important;
-  }
-}
 section.erklaerung h1 {
   font-size: 1.5rem;
   color: #1e5f8a;
diff --git a/slides/223015b/02-bild-audio-video.md b/slides/223015b/02-bild-audio-video.md
index 24e77f7..3681a2d 100644
--- a/slides/223015b/02-bild-audio-video.md
+++ b/slides/223015b/02-bild-audio-video.md
@@ -72,18 +72,6 @@ section.aufgabe footer {
 }
 section.erklaerung {
   font-size: 1.1rem;
-  background: repeating-linear-gradient(
-    135deg,
-    #e3f2fd,
-    #e3f2fd 40px,
-    #fff 40px,
-    #fff 80px
-  ) !important;
-}
-@media print {
-  section.erklaerung {
-    background: #e3f2fd !important;
-  }
 }
 section.erklaerung h1 {
   font-size: 1.5rem;
diff --git a/slides/223015b/03-speichermedien-schnittstellen.md b/slides/223015b/03-speichermedien-schnittstellen.md
index 5fca827..1885a3e 100644
--- a/slides/223015b/03-speichermedien-schnittstellen.md
+++ b/slides/223015b/03-speichermedien-schnittstellen.md
@@ -72,18 +72,6 @@ section.aufgabe footer {
 }
 section.erklaerung {
   font-size: 1.1rem;
-  background: repeating-linear-gradient(
-    135deg,
-    #e3f2fd,
-    #e3f2fd 40px,
-    #fff 40px,
-    #fff 80px
-  ) !important;
-}
-@media print {
-  section.erklaerung {
-    background: #e3f2fd !important;
-  }
 }
 section.erklaerung h1 {
   font-size: 1.5rem;
diff --git a/slides/223015c/01-geschichte-grundlagen-html.md b/slides/223015c/01-geschichte-grundlagen-html.md
index 2ee13c4..13d56aa 100644
--- a/slides/223015c/01-geschichte-grundlagen-html.md
+++ b/slides/223015c/01-geschichte-grundlagen-html.md
@@ -72,18 +72,6 @@ section.aufgabe footer {
 }
 section.erklaerung {
   font-size: 1.1rem;
-  /**background: repeating-linear-gradient(
-    135deg,
-    #fce4ec,
-    #fce4ec 40px,
-    #fff 40px,
-    #fff 80px
-  ) !important;**/
-}
-@media print {
-  section.erklaerung {
-    background: #fce4ec !important;
-  }
 }
 section.erklaerung h1 {
   font-size: 1.5rem;
diff --git a/slides/223015c/02-netzwerke-protokolle-css.md b/slides/223015c/02-netzwerke-protokolle-css.md
index d1dbde3..58ded68 100644
--- a/slides/223015c/02-netzwerke-protokolle-css.md
+++ b/slides/223015c/02-netzwerke-protokolle-css.md
@@ -73,18 +73,6 @@ section.glossar {
 }
 section.erklaerung {
   font-size: 1.1rem;
-  /**background: repeating-linear-gradient(
-    135deg,
-    #fce4ec,
-    #fce4ec 40px,
-    #fff 40px,
-    #fff 80px
-  ) !important;**/
-}
-@media print {
-  section.erklaerung {
-    background: #fce4ec !important;
-  }
 }
 section.erklaerung h1 {
   font-size: 1.5rem;