Tweak for code font sizes in headers to make them more readable.

[SVN r56028]

doc/html/boostbook.css

@@ -116,9 +116,10 @@
     h1 tt.computeroutput { font-size: 140% }
     h2 tt.computeroutput { font-size: 140% }
     h3 tt.computeroutput { font-size: 130% }
-    h4 tt.computeroutput { font-size: 120% }
-    h5 tt.computeroutput { font-size: 110% }
-    h6 tt.computeroutput { font-size: 100% }
+    h4 tt.computeroutput { font-size: 130% }	
+    h5 tt.computeroutput { font-size: 130% }
+    h6 tt.computeroutput { font-size: 130% }
+
 
 /*=============================================================================
     Author
@@ -217,7 +218,10 @@
        float: right;
        padding: 0.5pc;
     }
-
+	
+    /* Code on toc */
+    .toc .computeroutput { font-size: 120% }
+	
 /*=============================================================================
     Tables
 =============================================================================*/