Add font family to the Snow White theme tweaks

themes/tiddlywiki/snowwhite/ThemeTweaks.tid

@@ -22,11 +22,14 @@ You can tweak certain aspects of the ''Snow White'' theme.
 * Dropdown background colour mapping: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/colourmappings" index="dropdownbackground" default="" type="input"/>
 * Dropdown border colour mapping: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/colourmappings" index="dropdownborder" default="" type="input"/>
 
+! Settings
+
+* Font family: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/settings" index="fontfamily" default="" type="input"/>
+
 ! Sizes
 
 * Font size: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/metrics" index="fontsize" default="" type="input"/>
 * Line height: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/metrics" index="lineheight" default="" type="input"/>
-
 * Story left position //(the distance between the left of the screen and the left margin of the story river or tiddler area)//: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/metrics" index="storyleft" default="" type="input"/>
 * Story top position //(the distance between the top of the screen ad the top margin of the story river or tiddler area)//: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/metrics" index="storytop" default="" type="input"/>
 * Story right //(the distance between the left side of the screen and the left margin of the sidebar area)//: <$edit tiddler="$:/themes/tiddlywiki/snowwhite/metrics" index="storyright" default="" type="input"/>

themes/tiddlywiki/snowwhite/base.tid

@@ -64,7 +64,7 @@ background-image: -ms-linear-gradient($gradient$);
 */
 
 html {
-	font-family: "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
+	font-family: {{$:/themes/tiddlywiki/snowwhite/settings##fontfamily}};
 }
 
 body {

themes/tiddlywiki/snowwhite/settings.tid

@@ -0,0 +1,4 @@
+title: $:/themes/tiddlywiki/snowwhite/settings
+type: application/x-tiddler-dictionary
+
+fontfamily: `"Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif`