diff --git a/docs/installation/basic-installation.rst b/docs/installation/basic-installation.rst
index 486e6863b7b..01981aa4fbe 100644
--- a/docs/installation/basic-installation.rst
+++ b/docs/installation/basic-installation.rst
@@ -1,7 +1,15 @@
+.. raw:: html
+
+    <script>
+    document.addEventListener('DOMContentLoaded', function() {
+      activateTab(getOS());
+    });
+    </script>
+
 .. _basic-installation:
 
 Basic Installation
-------------------
+==================
 
 .. note::
 
@@ -68,7 +76,7 @@ and :pypi:`olefile` for Pillow to read FPX and MIC images::
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade Pillow
 
-    To install Pillow in MSYS2, see `Building on Windows using MSYS2/MinGW`_.
+    To install Pillow in MSYS2, see :ref:`building-from-source`.
 
 .. tab:: FreeBSD
 
@@ -87,11 +95,3 @@ and :pypi:`olefile` for Pillow to read FPX and MIC images::
         The `Pillow FreeBSD port
         <https://www.freshports.org/graphics/py-pillow/>`_ and packages
         are tested by the ports team with all supported FreeBSD versions.
-
-
-.. _Building on Linux:
-.. _Building on macOS:
-.. _Building on Windows:
-.. _Building on Windows using MSYS2/MinGW:
-.. _Building on FreeBSD:
-.. _Building on Android:
diff --git a/docs/installation/building-from-source.rst b/docs/installation/building-from-source.rst
index 8f4ef9e3e4a..349d191a68a 100644
--- a/docs/installation/building-from-source.rst
+++ b/docs/installation/building-from-source.rst
@@ -1,12 +1,20 @@
+.. raw:: html
+
+    <script>
+    document.addEventListener('DOMContentLoaded', function() {
+      activateTab(getOS());
+    });
+    </script>
+
 .. _building-from-source:
 
 Building From Source
---------------------
+====================
 
 .. _external-libraries:
 
 External Libraries
-^^^^^^^^^^^^^^^^^^
+------------------
 
 .. note::
 
@@ -221,7 +229,7 @@ Many of Pillow's features require external libraries:
     This has been tested within the Termux app on ChromeOS, on x86.
 
 Installing
-^^^^^^^^^^
+----------
 
 Once you have installed the prerequisites, to install Pillow from the source
 code on PyPI, run::
@@ -256,7 +264,7 @@ After navigating to the Pillow directory, run::
 .. _compressed archive from PyPI: https://pypi.org/project/pillow/#files
 
 Build Options
-"""""""""""""
+^^^^^^^^^^^^^
 
 * Environment variable: ``MAX_CONCURRENCY=n``. Pillow can use
   multiprocessing to build the extension. Setting ``MAX_CONCURRENCY``
@@ -298,3 +306,12 @@ Build Options
 Sample usage::
 
     python3 -m pip install --upgrade Pillow -C [feature]=enable
+
+.. _old-versions:
+
+Old Versions
+============
+
+You can download old distributions from the `release history at PyPI
+<https://pypi.org/project/pillow/#history>`_ and by direct URL access
+eg. https://pypi.org/project/pillow/1.0/.
diff --git a/docs/installation/index.rst b/docs/installation/index.rst
index 9e6e5eeecdf..a94204b6bbe 100644
--- a/docs/installation/index.rst
+++ b/docs/installation/index.rst
@@ -8,4 +8,3 @@ Installation
   python-support
   platform-support
   building-from-source
-  old-versions
diff --git a/docs/installation/old-versions.rst b/docs/installation/old-versions.rst
deleted file mode 100644
index 445a70d4ebf..00000000000
--- a/docs/installation/old-versions.rst
+++ /dev/null
@@ -1,8 +0,0 @@
-.. _old-versions:
-
-Old Versions
-------------
-
-You can download old distributions from the `release history at PyPI
-<https://pypi.org/project/pillow/#history>`_ and by direct URL access
-eg. https://pypi.org/project/pillow/1.0/.
diff --git a/docs/installation/platform-support.rst b/docs/installation/platform-support.rst
index 602941c3c5a..9ae97d70ad2 100644
--- a/docs/installation/platform-support.rst
+++ b/docs/installation/platform-support.rst
@@ -1,7 +1,7 @@
 .. _platform-support:
 
 Platform Support
-----------------
+================
 
 Current platform support for Pillow. Binary distributions are
 contributed for each release on a volunteer basis, but the source
@@ -10,7 +10,7 @@ general, we aim to support all current versions of Linux, macOS, and
 Windows.
 
 Continuous Integration Targets
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+------------------------------
 
 These platforms are built and tested for every change.
 
@@ -66,7 +66,7 @@ These platforms are built and tested for every change.
 
 
 Other Platforms
-^^^^^^^^^^^^^^^
+---------------
 
 These platforms have been reported to work at the versions mentioned.
 
diff --git a/docs/installation/python-support.rst b/docs/installation/python-support.rst
index 8d7db8d3a48..dd5765b6b70 100644
--- a/docs/installation/python-support.rst
+++ b/docs/installation/python-support.rst
@@ -1,7 +1,7 @@
 .. _python-support:
 
 Python Support
---------------
+==============
 
 Pillow supports these Python versions.
 
@@ -12,8 +12,3 @@ Pillow supports these Python versions.
 .. csv-table:: Older versions
    :file: older-versions.csv
    :header-rows: 1
-
-.. _Linux Installation:
-.. _macOS Installation:
-.. _Windows Installation:
-.. _FreeBSD Installation: