resize logo and keep it centered

Author: basnijholt

README.rst

@@ -10,7 +10,10 @@
 
 .. raw:: html
 
-   <video autoplay loop muted><source src="_static/logo_docs.mp4" type="video/mp4"></video>
+   <video autoplay loop muted style="width: 400px; max-width: 100%; margin: 0 auto; display:block;">
+      <source src="_static/logo_docs.mp4" type="video/mp4">
+   </video>
+   <br>
 
 ``adaptive`` is an open-source Python library designed to
 make adaptive parallel function evaluation simple. With ``adaptive`` you