prevent banner title wrapping on mobile by reducing font size

On smaller screens, the desktop-sized banner title does not fit on one line and
can break within the title word at arbitrary character boundaries.

At <=450px, reduce `big` from 400% to 300% so the title stays on one line and
remains readable.

Author: ritorhymes

assets/sass/main.scss

@@ -78,6 +78,11 @@ div.feature-matrix {
     vertical-align: center;
   }
 }
+@media screen and (max-width: 450px) {
+  big {
+    font-size: 300%;
+  }
+}
 @media screen and (max-width: 767px) {
   body {
     margin-right: 3%;