Make dashboard totals smaller if numbers are big

Numbers over a billion overflow the two column layout. Numbers over one
hundred thousand overflow the three column layout.

This commit makes the type size smaller in these cases, so that the
numbers still fit in the boxes.

app/assets/stylesheets/components/big-number.scss

@@ -85,7 +85,8 @@
       outline: 3px solid $yellow;
     }
 
-    .big-number {
+    .big-number,
+    .big-number-smaller {
       background: transparent;
     }