Fix Jumbotron styling

Author: logankilpatrick

index.html

@@ -97,7 +97,7 @@ <h2 class="archive__item-title">GeoRegions.jl</h2>
   </div>
 
 <!-- https://getbootstrap.com/docs/4.0/components/jumbotron/ -->
-<div class="jumbotron">
+<div class="jumbotron" style="text-align: center; margin-right: 20%; margin-left: 20%;">
   <h1 class="display-4">What can a technologist do about Climate Change?</h1>
   <p class="lead">Bret Victor, in 2015, published a <a href="http://worrydream.com/ClimateChange/#tools-technical">famous article</a> about how to contribute to the climate change solution.</p>
   <hr class="my-4">