Fix article padding on mobile

Fixes #115

layouts/_default/single.html

@@ -4,7 +4,7 @@
 {{ end }}
 
 {{ define "main" }}
-  <article class="flex-l flex-wrap justify-between mw8 center">
+  <article class="flex-l flex-wrap justify-between mw8 center ph3 ph0-l">
 
     <header class="mt4 w-100">
       <p class="f6 b helvetica tracked">