Forced footer to always be at the bottom of the window.

css/main.css

@@ -1,14 +1,20 @@
 body {
+    background-color: #f5f5f5;
+    color: #212121;
+    display: flex;
+    flex-direction: column;
     font-family: 'RobotoDraft', 'Roboto', 'Helvetica Neue, Helvetica, Arial', sans-serif;
     font-style: normal;
     font-weight: 300;
     font-size: 16px;
+    height: 100vh;
     line-height: 1.4;
-    color: #212121;
-    background-color: #f5f5f5;
     -webkit-font-smoothing: antialiased;
     text-rendering: optimizeLegibility;
 }
+body > section:last-of-type {
+    flex: 1;
+}
 
 section {
     padding: 1em 1em;