update slide styles to blue theme and add repo links

slides/2025-12-20-termin-1-geschichte-grundlagen-html.md

@@ -11,7 +11,7 @@ title: "Termin 1: Geschichte, Grundlagen & HTML"
 <style>
 :root {
   --color-foreground: #1a1a2e;
-  --color-highlight: #4ecca3;
+  --color-highlight: #5da9e9;
   --color-dimmed: #4a4a6a;
 }
 section.invert {
@@ -25,9 +25,9 @@ h2 {
 }
 pre {
   background: #0f0f23;
-  color: #4ecca3;
+  color: #5da9e9;
   border-radius: 8px;
-  border-left: 3px solid #4ecca3;
+  border-left: 3px solid #5da9e9;
 }
 pre code {
   background: transparent;
@@ -35,7 +35,7 @@ pre code {
 }
 code {
   background: #1a1a2e;
-  color: #4ecca3;
+  color: #5da9e9;
   padding: 0.15em 0.4em;
   border-radius: 4px;
 }
@@ -46,6 +46,7 @@ a {
 
 <!-- _class: invert -->
 <!-- _header: '' -->
+<!-- _footer: '' -->
 <!-- _backgroundColor: black -->
 
 ![bg fit opacity:0.4](./assets/background-termin-1.png)
@@ -58,6 +59,8 @@ Hochschule der Medien Stuttgart
 
 **Wintersemester 2025/26**
 
+[https://git.librete.ch/hdm/223015c](https://git.librete.ch/hdm/223015c)
+
 ---
 
 <!-- _class: lead -->

slides/2026-01-10-termin-2-netzwerke-protokolle-css.md

@@ -46,6 +46,7 @@ a {
 
 <!-- _class: invert -->
 <!-- _header: '' -->
+<!-- _footer: '' -->
 <!-- _backgroundColor: black -->
 
 ![bg fit opacity:0.4](./assets/background-termin-2.png)

slides/2026-01-24-termin-3-interaktivitaet-javascript.md

@@ -46,6 +46,7 @@ a {
 
 <!-- _class: invert -->
 <!-- _header: '' -->
+<!-- _footer: '' -->
 <!-- _backgroundColor: black -->
 
 ![bg fit opacity:0.4](./assets/background-termin-3.png)