[style] [upgrade] moved to bootstrap 3
diff --git a/website/templates/html/blog_footer.html b/website/templates/html/blog_footer.html
index e439d14..ecb463c 100644
--- a/website/templates/html/blog_footer.html
+++ b/website/templates/html/blog_footer.html
@@ -1,4 +1,4 @@
-<div class="span12">
+<div class="col-span-12">
 	<hr />
 	{% if categories %}
 	<h5>Explore posts by categories</h5>