fix the font-family var by using inherit instead of empty string, fix...

fix the font-family var by using inherit instead of empty string, fix font-weight in docs for jumbotron

docs/assets/css/bootstrap.css

@@ -310,9 +310,9 @@ h4,
 h5,
 h6 {
   margin: 0;
-  font-family: '';
+  font-family: inherit;
   font-weight: normal;
-  color: '';
+  color: inherit;
   text-rendering: optimizelegibility;
 }
 h1 small,

docs/assets/css/docs.css

@@ -63,6 +63,7 @@ hr.soften {
 .jumbotron h1 {
   margin-bottom: 9px;
   font-size: 81px;
+  font-weight: bold;
   letter-spacing: -1px;
   line-height: 1;
 }

less/variables.less

@@ -50,9 +50,9 @@
 @baseLineHeight:        18px;
 @altFontFamily:         Georgia, "Times New Roman", Times, serif;
 
-@headingsFontFamily:    ''; // empty to use BS default, @baseFontFamily
-@headingsFontWeight:    normal; // instead of browser default, bold
-@headingsColor:         ''; // empty to use BS default, @textColor
+@headingsFontFamily:    inherit; // empty to use BS default, @baseFontFamily
+@headingsFontWeight:    normal;  // instead of browser default, bold
+@headingsColor:         inherit; // empty to use BS default, @textColor
 
 
 // Tables