Stop headings and nav falling back to a cursive font on mobile

The theme styled the nav, all headings and the comments watermark with
'Coda', cursive, sans-serif, pulling Coda from Google Fonts. That font
load was never ported, so browsers moved to the next entry in the stack
-- the generic cursive family -- and rendered those elements as a script
face on any device that ships one, which phones do. It went unnoticed
because this server's Chromium has no cursive font installed and so fell
through to sans-serif.

Those three rules now use Arial, Helvetica, sans-serif, matching the body
text, rather than depending on a webfont that is no longer loaded.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/styles/global.css

@@ -506,7 +506,7 @@ del {
 
 #smallbusiness-main-menu {
     float: right;
-    font-family: 'Coda',cursive,sans-serif;
+    font-family: Arial,Helvetica,sans-serif;
     line-height: 1;
 	max-width: 610px;
 	color:#EEEEEE;
@@ -735,7 +735,7 @@ margin:0;
 /* Design Elements 
 ------------------------------------------------------------- */
 h1, h1 a, h1 a:visited, h1 a:hover, h2, h2 a, h2 a:visited, h2 a:hover, h3, h4, h5, h6 {
-	font-family: 'Coda',cursive,sans-serif; 
+	font-family: Arial,Helvetica,sans-serif; 
     font-weight: normal;
     line-height: 1.25;
     margin: 0 0 10px;
@@ -1235,7 +1235,7 @@ p.postmetadata {
 }
 
 #commentsbox .watermark {
-	font-family: 'Coda',cursive,sans-serif;
+	font-family: Arial,Helvetica,sans-serif;
     font-size: 17px;
     text-align: center;
     text-shadow: none;