fix layout bug on API Guide landing pages

Change-Id: Ic757d26c29cd06c33dc62816698b68a9b5fe869a
diff --git a/tools/droiddoc/templates-sdk/assets/css/default.css b/tools/droiddoc/templates-sdk/assets/css/default.css
index bc083a9..09e6450 100644
--- a/tools/droiddoc/templates-sdk/assets/css/default.css
+++ b/tools/droiddoc/templates-sdk/assets/css/default.css
@@ -4055,6 +4055,7 @@
 }
 .landing-docs {
   clear:left;
+  overflow:hidden;
 }
 .landing-docs h3 {
   font-size:14px;