Fix videos on mobile (responsive design); small changes

README.md

 
 Currently supported features:
 
-* **Image tracking**, also known as natural feature tracking. Use it to track detailed images (such as book covers, cartoons or photos) for AR.
+* **Image tracking**, also known as natural feature tracking. Use it to track detailed images such as: book covers, cartoons and photos.
 
 ![WebAR demo](docs/img/demo-aframe.gif) ![WebAR demo](docs/img/demo-hello.gif)
 

docs/getting-started/index.md

 
 Currently supported features:
 
-* **Image tracking**, also known as natural feature tracking. Use it to track detailed images (such as book covers, cartoons or photos) for AR.
+* **Image tracking**, also known as natural feature tracking. Use it to track detailed images such as: book covers, cartoons and photos.
 
 ![WebAR demo](../img/demo-aframe.gif) ![WebAR demo](../img/demo-hello.gif)
 

docs_overrides/style/extra.css

     background-repeat: repeat;
 }
 
+/* Responsive videos */
+
+.md-typeset video {
+    height: auto;
+    max-width: 100%;
+}
+
 /* Share buttons */
 
 .share-buttons {

mkdocs.yml

       - 'Set up a web server': 'getting-started/set-up-a-web-server.md'
       - 'Set up the tracker': 'getting-started/set-up-the-tracker.md'
       - 'Set up the session': 'getting-started/set-up-the-session.md'
-      - 'Create the augmented scene': 'getting-started/create-the-augmented-scene.md'
+      - 'Create the augmented scene (supporters)': 'getting-started/create-the-augmented-scene.md'
       - 'Activate your webcam': 'getting-started/activate-your-webcam.md'
       - 'Next steps': 'getting-started/next-steps.md'
     - 'Guidelines for Images': 'getting-started/guidelines-for-images.md'