Make boxes on main page sligthly higher.

Without that change, documentation box is too higher and text overflows
the box when font is rather wide, like DejaVu Sans, used on many open-
source systems that aren't Android.

source/style.css

@@ -94,7 +94,7 @@ div a:hover, #header a:hover {
 
 .box {
     width: 15em;
-    height: 9em;
+    height: 10em;
     margin: 0.5em;
     padding: 0 1em 1em 1em;
     float: left;