diff -r d4ec02c51c91 -r af15590802a4 assets/stylesheets/bootstrap/_utilities.scss
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/assets/stylesheets/bootstrap/_utilities.scss	Thu Jun 15 12:17:09 2017 +0200
@@ -0,0 +1,55 @@
+//
+// Utility classes
+// --------------------------------------------------
+
+
+// Floats
+// -------------------------
+
+.clearfix {
+  @include clearfix;
+}
+.center-block {
+  @include center-block;
+}
+.pull-right {
+  float: right !important;
+}
+.pull-left {
+  float: left !important;
+}
+
+
+// Toggling content
+// -------------------------
+
+// Note: Deprecated .hide in favor of .hidden or .sr-only (as appropriate) in v3.0.1
+.hide {
+  display: none !important;
+}
+.show {
+  display: block !important;
+}
+.invisible {
+  visibility: hidden;
+}
+.text-hide {
+  @include text-hide;
+}
+
+
+// Hide from screenreaders and browsers
+//
+// Credit: HTML5 Boilerplate
+
+.hidden {
+  display: none !important;
+}
+
+
+// For Affix plugin
+// -------------------------
+
+.affix {
+  position: fixed;
+}