adding visual examples of package features on index page

* the sphinx gallery examples are used to visualize the different
  features of the library that link to the getting started page

docs/src/getting-started.rst

@@ -4,6 +4,8 @@ Getting started
 A small introduction to all methods implemented in scikit-matter.
 For a detailed explaination, please look at the :ref:`selection-api`
 
+.. _getting_started-selection:
+
 Features and Samples Selection
 ------------------------------
 
@@ -34,6 +36,8 @@ Examples
    :start-line: 4
 
 
+.. _getting_started-reconstruction:
+
 Reconstruction Measures
 -----------------------
 
@@ -57,6 +61,8 @@ Examples
 .. include:: examples/reconstruction/index.rst
    :start-line: 4
 
+.. _getting_started-pcovr:
+
 Principal Covariates Regression
 -------------------------------
 

docs/src/index.rst

@@ -1,11 +1,81 @@
-scikit-matter
-=============
+What is scikit-matter?
+======================
 
 scikit-matter is a toolbox of methods developed in the
 computational chemical and materials science community, following the
 `scikit-learn <https://scikit.org/>`_ API
 and coding guidelines to promote usability and interoperability with existing workflows.
 
+.. raw:: html
+
+    <div class="container">
+        <div class="row">
+            <div class="col-lg-6 col-md-6 col-sm-6 col-xs-12 d-flex">
+                <div class="card text-center intro-card shadow">
+                <div class="card-body flex-fill">
+                    <h5 class="card-title">
+
+
+.. only:: html
+
+  .. image:: /examples/selection/images/thumb/sphx_glr_FeatureSelection-WHODataset_thumb.png
+    :alt:
+
+  :ref:`getting_started-selection`
+
+.. raw:: html
+
+                    </h5>
+                    <p class="card-text">Supervised and unsupervised selection
+                    methods based on
+                    CUR matrix decomposition and Farthest Point Sampling.</p>
+                </div>
+                </div>
+            </div>
+            <div class="col-lg-6 col-md-6 col-sm-6 col-xs-12 d-flex">
+                <div class="card text-center intro-card shadow">
+                <div class="card-body flex-fill">
+                    <h5 class="card-title">
+
+.. only:: html
+
+  .. image:: /examples/pcovr/images/thumb/sphx_glr_PCovR_thumb.png
+    :alt:
+
+  :ref:`getting_started-pcovr`
+
+.. raw:: html
+
+                    </h5>
+                    <p class="card-text">Utilises a combination between a PCA-like and a LR-like loss
+                    to determine the decomposition matrix to project feature into latent space</p>
+                </div>
+                </div>
+            </div>
+            <div class="col-lg-6 col-md-6 col-sm-6 col-xs-12 d-flex">
+                <div class="card text-center intro-card shadow">
+                <div class="card-body flex-fill">
+                    <h5 class="card-title">
+
+.. only:: html
+
+  .. image:: /examples/reconstruction/images/thumb/sphx_glr_PlotLFRE_thumb.png
+    :alt:
+
+  :ref:`getting_started-reconstruction`
+
+.. raw:: html
+
+                    </h5>
+                    <p class="card-text">Error measures for quantifying the
+                    linear decodable information capacity between features</p>
+                </div>
+                </div>
+            </div>
+        </div>
+    </div>
+
+
 
 .. include:: ../../README.rst
    :start-after: marker-issues
@@ -21,6 +91,5 @@ and coding guidelines to promote usability and interoperability with existing wo
   contributing
   bibliography
 
-
 If you would like to contribute to scikit-matter, check out our :ref:`contributing`
 page!