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 d4906d7..cf1f00a 100644
--- a/courses/223015b/slides/2025-12-19-termin-0-intro.md
+++ b/courses/223015b/slides/2025-12-19-termin-0-intro.md
@@ -31,7 +31,7 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #1e5f8a;
+  color: #5fb3e4;
   border-radius: 8px;
   border-left: 3px solid #1e5f8a;
 }
@@ -41,7 +41,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #1e5f8a;
+  color: #5fb3e4;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -60,7 +60,7 @@ section.klausur footer {
 <!-- _header: '' -->
 <!-- _backgroundColor: #000 -->
 
-![bg fit opacity:0.4](./assets/digital-landscape.png)
+![bg cover opacity:0.2](./assets/radek-grzybowski-eBRTYyjwpRY-unsplash.jpg)
 
 # Dateiformate, Schnittstellen, Speichermedien & Distributionswege
 
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 a47cc50..5c2c809 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
@@ -31,7 +31,7 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #1e5f8a;
+  color: #5fb3e4;
   border-radius: 8px;
   border-left: 3px solid #1e5f8a;
 }
@@ -41,7 +41,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #1e5f8a;
+  color: #5fb3e4;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -60,7 +60,7 @@ section.klausur footer {
 <!-- _header: '' -->
 <!-- _backgroundColor: #000 -->
 
-![bg fit opacity:0.4](./assets/digital-landscape.png)
+![bg cover opacity:0.2](./assets/radek-grzybowski-eBRTYyjwpRY-unsplash.jpg)
 
 # Dateiformate, Schnittstellen, Speichermedien & Distributionswege
 
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 b567ef6..02355ed 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
@@ -31,7 +31,7 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #1e5f8a;
+  color: #5fb3e4;
   border-radius: 8px;
   border-left: 3px solid #1e5f8a;
 }
@@ -41,7 +41,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #1e5f8a;
+  color: #5fb3e4;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -61,7 +61,7 @@ section.klausur footer {
 <!-- _footer: '' -->
 <!-- _backgroundColor: #000 -->
 
-![bg fit opacity:0.4](./assets/digital-landscape.png)
+![bg cover opacity:0.2](./assets/radek-grzybowski-eBRTYyjwpRY-unsplash.jpg)
 
 # Dateiformate, Schnittstellen, Speichermedien & Distributionswege
 
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 ba323ac..71b4ada 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
@@ -31,7 +31,7 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #1e5f8a;
+  color: #5fb3e4;
   border-radius: 8px;
   border-left: 3px solid #1e5f8a;
 }
@@ -41,7 +41,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #1e5f8a;
+  color: #5fb3e4;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -60,7 +60,7 @@ section.klausur footer {
 <!-- _header: '' -->
 <!-- _backgroundColor: #000 -->
 
-![bg fit opacity:0.4](./assets/digital-landscape.png)
+![bg cover opacity:0.2](./assets/radek-grzybowski-eBRTYyjwpRY-unsplash.jpg)
 
 # Dateiformate, Schnittstellen, Speichermedien & Distributionswege
 
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 7049681..85c1427 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
@@ -31,7 +31,7 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #1e5f8a;
+  color: #5fb3e4;
   border-radius: 8px;
   border-left: 3px solid #1e5f8a;
 }
@@ -41,7 +41,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #1e5f8a;
+  color: #5fb3e4;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -61,7 +61,7 @@ section.klausur footer {
 <!-- _footer: '' -->
 <!-- _backgroundColor: #000 -->
 
-![bg fit opacity:0.4](./assets/digital-landscape.png)
+![bg cover opacity:0.2](./assets/radek-grzybowski-eBRTYyjwpRY-unsplash.jpg)
 
 # Dateiformate, Schnittstellen, Speichermedien & Distributionswege
 
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 309c025..2966a4a 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
@@ -31,7 +31,7 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #1e5f8a;
+  color: #5fb3e4;
   border-radius: 8px;
   border-left: 3px solid #1e5f8a;
 }
@@ -41,7 +41,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #1e5f8a;
+  color: #5fb3e4;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -61,7 +61,7 @@ section.klausur footer {
 <!-- _footer: '' -->
 <!-- _backgroundColor: #000 -->
 
-![bg fit opacity:0.4](./assets/digital-landscape.png)
+![bg cover opacity:0.2](./assets/radek-grzybowski-eBRTYyjwpRY-unsplash.jpg)
 
 # Dateiformate, Schnittstellen, Speichermedien & Distributionswege
 
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 2f54c79..71a8131 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
@@ -12,7 +12,7 @@ title: "Termin 2: Netzwerke, Protokolle & CSS"
 :root {
   --color-foreground: #1a1a2e;
   --color-highlight: #d63384;
-  --color-dimmed: #4a4a6a;
+  --color-dimmed: #dde0e4;
 }
 section.invert {
   --color-foreground: #fff;
@@ -40,8 +40,8 @@ pre code {
   color: inherit;
 }
 code {
-  background: #1a1a2e;
-  color: #d63384;
+  background: #f0e6eb;
+  color: #1a1a2e;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
diff --git a/themes/custom-theme.css b/themes/custom-theme.css
index adbdb37..77db44a 100644
--- a/themes/custom-theme.css
+++ b/themes/custom-theme.css
@@ -6,6 +6,7 @@ section {
   background-color: #f0f8ff;
   color: #2c3e50;
   font-size: 0.85em;
+  --color-dimmed: #e0e6eb;
 }
 
 h1 {
@@ -21,13 +22,17 @@ ul, ol {
   font-size: 0.8em;
 }
 
-code {
-  background-color: #ecf0f1;
-  color: #2c3e50;
+section code {
+  color: #1a1a1a;
   padding: 2px 4px;
   border-radius: 3px;
 }
 
+/* Preserve explicit SVG fill colors */
+section svg *[fill] {
+  fill: revert;
+}
+
 blockquote {
   border-left: 4px solid #3498db;
   background-color: #ecf0f1;