Create chapter key as guide for learners and developers

textbook/.gitignore

@@ -1 +1,3 @@
 /.quarto/
+
+/_*.local

textbook/_quarto.yml

@@ -7,6 +7,7 @@ book:
   date: "7/29/2024"
   chapters:
     - index.qmd
+    - chapter-key.qmd
     # - chapter_1.qmd
     - summary.qmd
 

textbook/chapter-key.qmd

@@ -0,0 +1,127 @@
+# Chapter key {.unnumbered}
+
+::: {.callout-note title="Learning outcomes" collapse=false}
+Every chapter starts with the "Learning outcomes",
+which describe what you will learn from this chapter.
+To make these learning outcomes more useful to you as a reader,
+we have expanded them to include a summary of the "solution" for each outcome,
+instead of just stating what you are to learn in the chapter.
+
+For example,
+instead of simply stating:
+"Explain the main advantage of visualizing data instead"
+we would write:
+"Explain that the main advantage of visualizing data instead of presenting it with numbers is that they are easier to interpret for humans.
+
+As such,
+the learning objectives also serve as the summary of each chapter.
+:::
+
+## A heading
+
+The main text will go here.
+This can cover both practical
+and theoretical aspects of data visualization.
+
+### A sub-heading
+
+These will be used to divide content further.
+
+## Exercises
+
+::::: {.callout-default .ex-prompt}
+
+Exercises aim to engage you actively with the material,
+both to make it more fun to learn
+and to improve your learning.
+Try to solve the exercise on your own first,
+before looking at the hint and the solution;
+this active engagement is what aids your learning.
+Click the hint below to expand it.
+
+:::: {.callout-default .ex-hint}
+
+Before looking at the solution,
+try to use the hint to figure out the answer.
+
+::: {.callout-default .ex-solution}
+
+The solution is inside the "Hint" section,
+to encourage you to first try to use the hint to solve the exercise.
+
+:::
+
+::::
+
+:::::
+
+## Coding content
+
+Coding content will often include a panel with multiple tabs,
+so that you can easily see what the same code looks like
+for different visualization packages.
+These sections also include explanations
+that are specific to the code of a certain package,
+rather than being about data visualization in general.
+
+::: {.panel-tabset}
+
+### Package One
+
+```{python}
+# Code for the first package, e.g.:
+range(5)
+
+```
+
+### Package Two
+
+```{r}
+# Code for the second package, e.g.:
+seq(5)
+```
+
+:::
+
+::: {.column-margin}
+
+**Optional content**
+
+Content in the margin is optional
+and can include
+fun factual tidbits,
+historical explanations,
+etymology,
+and more.
+
+:::
+
+## Deep dive
+
+<details><summary>Click to expand the optional deep dive or proceed to the exercise mission.</summary>
+
+Every chapter contains a deep dive
+with optional content.
+This section elaborates on a concept that was learned in the chapter,
+and often contains more challenging content.
+
+</details>
+
+## Exercise mission
+
+In addition to the exercises spread throughout the content,
+each chapter contains a set of connected exercises in the end
+that interweaves the content learned throughout the chapter.
+This challenges you to deepen your understanding
+as it requires comprehension of how the content fit together
+rather than solely mastering each section in isolation.
+
+To help you along the way on these exercises,
+you will be able to converse with an avatar from the fictional setting of the book.
+These will make it clear what your goal is for each section
+and help you along the way if you get stuck.
+
+Before you get started with this section,
+make sure you review the chapter summary
+in the learning outcomes
+and that you understand each of the items there.