Fix footer (CSS).

static/css/bootstrap.css

@@ -7,13 +7,17 @@
 /*! normalize.css v3.0.1 | MIT License | git.io/normalize */
 html {
   font-family: sans-serif;
+  height: 100%;
   -webkit-text-size-adjust: 100%;
       -ms-text-size-adjust: 100%;
 }
+
 body {
   margin: 0;
+  height: 100%;
   padding-top: 100px;
 }
+
 article,
 aside,
 details,
@@ -1396,6 +1400,8 @@ pre code {
   padding-left: 15px;
   margin-right: auto;
   margin-left: auto;
+  height: 100%;
+  min-height: 100%;
 }
 @media (min-width: 768px) {
   .container {
@@ -6203,10 +6209,13 @@ button.close {
 }
 
 .footer {
-  position: absolute;
-  bottom: 0;
   width: 100%;
+  position: relative;
+  margin-top: -60px;
   height: 60px;
+  clear: both;
+  background: #f5f5f5;
   padding-top: 20px;
-  background-color: #f5f5f5;
+  bottom: 0;
+  text-align: left;
 }