update introduction

LearnJsonEverything/Services/HelpContent.cs

@@ -10,7 +10,7 @@ use the `json-everything` libraries to their full potential!
 		Inside, you'll find a collection of lessons, each of which highlight a specific feature
 		provided by one of the libraries. For each lesson, you'll be given some background information,
 		possibly some links to various documentation, and a coding challenge along with some test
-		cases.  To move on to the next lesson, your code will need to make all test cases pass.
+		cases.  Make all the tests pass to move on to the next lesson.
 		
 		Want to skip ahead and work on a particular lesson? No problem: simply select the lesson
 		you'd like to work on from the pane on the left.  The navigation buttons will activate as
@@ -20,9 +20,13 @@ any time.
 		To assist you on your journey, the site will keep track of the lessons you've completed
 		as well as your solutions to them so that you can take a break and come back at any time
 		either to continue learning or to review the work you've done.
+
+		You can click <kbd>Reveal Solution</kbd> at any time to see the recommended solution, or
+		<kbd>Reset</kbd> to get the template back and clear the lesson state.
+
+		---
 		
-		**This site is 100% client-side. All operations are performed in your browser. There
-		is no server to send any of your data to.**
+		**This site is 100% client-side. All operations are performed in your browser.**
 		
 		---
 		

LearnJsonEverything/wwwroot/css/app.css

@@ -356,6 +356,11 @@ blockquote {
 	fill: rgb(175, 176, 177);
 }
 
+kbd {
+  border: solid 1px dimgray;
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
+}
+
 /*--- FEATURE ---*/
 
 .feature{