C++ docs: finish re-organzing the C++ docs entry

Instead of repeating the table of contents, provide a proper intro
page - based on the Github README - and group the remaining content
into Getting Started, Reference and Integration sections.

api/sixtyfps-cpp/docs/genindex.rst

@@ -0,0 +1,3 @@
+===========
+Index (C++)
+===========

api/sixtyfps-cpp/docs/index.rst

@@ -14,24 +14,80 @@ Welcome to SixtyFPS C++'s documentation!
 
 .. toctree::
    :maxdepth: 2
-   :caption: Contents:
+   :hidden:
-
+   :caption: Getting Started
-   intro.md
 
    cmake.md
 
-   getting_started.md
+   First Steps <getting_started.md>
+
+.. toctree::
+   :maxdepth: 2
+   :hidden:
+   :caption: Reference
 
    api/library_root
 
+   genindex
+
    language.rst
 
+.. toctree::
+   :maxdepth: 2
+   :hidden:
+   :caption: C++ / .60 Integration
+
    Type Mapping to C++ <types.md>
 
    Example Generated Code <generated_code.md>
 
-Indices and tables
+.. image:: https://github.com/sixtyfpsui/sixtyfps/workflows/CI/badge.svg
-==================
+   :target: https://github.com/sixtyfpsui/sixtyfps/actions
+   :alt: GitHub CI Build Status
+
+`SixtyFPS <https://sixtyfps.io/>`_ is a toolkit to efficiently develop fluid graphical user interfaces for any display: embedded devices and desktop applications.
+SixtyFPS C++ is the C++ API to interact with a SixtyFPS UI from C++.
+
+The .60 Markup Language
+=======================
+
+SixtyFPS comes with a markup language that is specifically designed for user interfaces. This language provides a
+powerful way to describe graphical elements, their placement, and the flow of data through the different states. It is a familiar syntax to describe the hierarchy
+of elements and property bindings. Here's the obligatory "Hello World":
+
+.. code-block:: 60-no-preview
+
+    HelloWorld := Window {
+        width: 400px;
+        height: 400px;
+
+        Text {
+           y: parent.width / 2;
+           x: parent.x + 200px;
+           text: "Hello, world";
+           color: blue;
+        }
+    }
+
+Check out the `language reference <markdown/langref.html>`_ for more details.
+
+Architecture
+============
+
+An application is composed of the business logic written in C++ and the `.60` user interface design markup, which
+is compiled to native code.
+
+.. image:: https://sixtyfps.io/resources/architecture.drawio.svg
+  :alt: Architecture Overview
+
+Developing
+==========
+
+You can create and edit `.60` files using our `SixtyFPS Visual Studio Code Extension <https://marketplace.visualstudio.com/items?itemName=SixtyFPS.sixtyfps-vscode>`_,
+which features syntax highlighting and live design preview.
+
+For a quick edit and preview cycle, you can also use the :code:`sixtyfps-viewer` command line tool, which can be installed using :code:`cargo install sixtyfps-viewer`,
+if you have `Cargo <https://marketplace.visualstudio.com/items?itemName=SixtyFPS.sixtyfps-vscode>`_ installed.
+
+In the next section you will learn how to install the SixtyFPS C++ library and the CMake build system integration.
 
-* :ref:`genindex`
-* :ref:`search`

docs/resources/sixtyfps-docs-highlight.html

@@ -90,7 +90,7 @@
 
       // The Sphinx/my_st generated HTML for code blocks does not use <code> tags, so highlight.js'
       // default selector "pre code" does not match. Let's do it by hand:
-      for (block of document.querySelectorAll("div.highlight-60 div.highlight pre")) {
+      for (block of document.querySelectorAll("div.highlight-60 div.highlight pre, div.highlight-60-no-preview div.highlight pre")) {
         hljs.highlightElement(block)
       }
     }