Tag Geant4 macro fenced blocks with 'default' so they pick up code-block styling

lab2_exampleB1/lab2.qmd

@@ -255,22 +255,22 @@ The real power of Geant4 is the ability to easily change simulation parameters u
 
 2. Add the following commands to your macro file:
 
-   ```
+   ```default
    # My custom run for Lab 2
    # Author: [Your Name]
-   
+
    # Initialize the kernel
    /run/initialize
-   
+
    # Set the particle to a proton
    /gun/particle proton
-   
+
    # Set the proton's kinetic energy to 150 MeV
    /gun/energy 150 MeV
-   
+
    # Print progress every 100 events
    /run/printProgress 100
-   
+
    # Run 1000 events
    /run/beamOn 1000
    ```
@@ -292,7 +292,7 @@ Let's create additional macro files to explore different simulation scenarios:
 
 1. Create a macro for electron simulation (`electron_beam.mac`):
 
-   ```
+   ```default
    /run/initialize
    /gun/particle e-
    /gun/energy 50 MeV
@@ -301,7 +301,7 @@ Let's create additional macro files to explore different simulation scenarios:
 
 2. Create a macro for neutron simulation (`neutron_beam.mac`):
 
-   ```
+   ```default
    /run/initialize
    /gun/particle neutron
    /gun/energy 14 MeV

lab3_modifyB1/lab3.qmd

@@ -262,7 +262,7 @@ Now let's compile your modified code and generate some data!
 
    Add these contents:
 
-   ```
+   ```default
    # Lab 3 Data Collection Run
    # Simulate 10,000 events with default 6 MeV gammas
 
@@ -575,7 +575,8 @@ Let's generate data for different particles and compare their energy deposition
    ```
 
    Add:
-   ```
+
+   ```default
    /run/numberOfThreads 1
    /run/initialize
    /gun/particle proton
@@ -591,7 +592,8 @@ Let's generate data for different particles and compare their energy deposition
    ```
 
    Add:
-   ```
+
+   ```default
    /run/numberOfThreads 1
    /run/initialize
    /gun/particle e-

lab4_exampleB3/lab4.qmd

@@ -164,7 +164,7 @@ That is the only file you need to edit. `EventAction.cc` is left untouched — t
 
    Add:
 
-   ```
+   ```default
    # Lab 4: PET scanner data run
 
    # Force single-threaded mode so we get ONE CSV file, not one per worker.