[major] upgrade to bootstrap 3
diff --git a/website/templates/html/blog_footer.html b/website/templates/html/blog_footer.html
index 8a84572..b4a574c 100644
--- a/website/templates/html/blog_footer.html
+++ b/website/templates/html/blog_footer.html
@@ -1,4 +1,4 @@
-<div class="col col-lg-12">
+<div class="col-md-12">
 	<hr />
 	{% if categories %}
 	<h5>Explore posts by categories</h5>