diff --git a/.themes/buutti.css b/.themes/buutti.css
index 0a0442f..b4e1310 100644
--- a/.themes/buutti.css
+++ b/.themes/buutti.css
@@ -42,4 +42,22 @@
.tableborderless td, th {
border: none!important;
border-collapse: collapse;
-}
\ No newline at end of file
+}
+
+section.extra {
+ background-color: #5d275d;
+ background-image: linear-gradient(to bottom, #401a40, #1d0c1d);
+ color: white;
+}
+section.extra a {
+ color: rgb(145, 255, 209);
+}
+
+section.exercise {
+ background-color: #29366f;
+ background-image: linear-gradient(to bottom, #20636a, #173742);
+ color: white;
+}
+section.exercise a {
+ color: rgb(211, 173, 255);
+}
diff --git a/13. Generics, IEnumerable and LINQ-slides.html b/13. Generics, IEnumerable and LINQ-slides.html
index 6aab362..faacf3c 100644
--- a/13. Generics, IEnumerable and LINQ-slides.html
+++ b/13. Generics, IEnumerable and LINQ-slides.html
@@ -83,7 +83,7 @@ GenericMethodExample<string>(Note: You could name the generic type as anything, e.g. <GenericType>. It is named <T> by convention.
-
+
Exercise 3: Asynchronous Loading
Re-create the exercise 2, but instead of using separate threads for "loading the data", use an asynchronous method LoadDataAsync()
diff --git a/14. Exceptions, Threads and Tasks.md b/14. Exceptions, Threads and Tasks.md
index b7f4156..cc2fef3 100644
--- a/14. Exceptions, Threads and Tasks.md
+++ b/14. Exceptions, Threads and Tasks.md
@@ -94,8 +94,7 @@ title: 14. Exceptions, Threads and Tasks
```
## Exercise 1: Debugging Exceptions
-
-
+
Create a savings calculator which asks the user for a target amount of money the user is aiming for (in integers), and the users monthly salary. For parsing, use the int.Parse() method instead of int.TryParse().
@@ -204,7 +203,7 @@ The method keeps executing indefinitely, but the main thread continues execution
```
## Exercise 2: Threaded Loading
-
+
Create a method `public static void LoadData()` which simulates loading resources by printing progress from $0 \%$ to $100 \%$. Increase the progress in a loop with $1 \%$ increments. Use the `Thread.Sleep()` method to wait $10\,\mathrm{ms}$ between each increment.
@@ -279,7 +278,7 @@ class Program
## Exercise 3: Asynchronous Loading
-
+
Re-create the exercise 2, but instead of using separate threads for "loading the data", use an asynchronous method `LoadDataAsync()`