initial wip theme

src/skins/vector/css/themes/_base.scss

@@ -1,3 +1,9 @@
+/* Open Sans lacks combining diacritics, so these will fall through
+   to the next font.  Helevetica's diacritics however do not combine
+   nicely with Open Sans (on OSX, at least) and result in a huge
+   horizontal mess.  Arial empirically gets it right, hence prioritising
+   Arial here. */
+$font-family: 'Open Sans', Arial, Helvetica, Sans-Serif;
 
 // typical text (dark-on-white in light skin)
 $primary-fg-color: #454545;