Address comments from PR review

Author: christinach

app/assets/stylesheets/variables/typography.scss

@@ -1,5 +1,5 @@
 $font-serif: 'Droid Serif', Georgia, Times, serif !default;
-$font-sans: 'Atkinson Hyperlegible','Times New Roman', sans-serif !default;
+$font-sans: 'Atkinson Hyperlegible','Dejavu Sans', Helvetica, sans-serif !default;
 $font-sans-alt: praxis-next-condensed, Helvetica, sans-serif !default;
 $font-mono: 'Lucida Console', Monaco, monospace !default;
 $text-color: #000 !default;