diff --git a/_layouts/default.html b/_layouts/default.html
index 3ba84b39..b8ef583e 100644
--- a/_layouts/default.html
+++ b/_layouts/default.html
@@ -43,11 +43,12 @@
       <section id="main_content" class="inner {{ page.title | downcase }}">
 
         <div id="horizontal_ad">
-          <!-- main: new site -->
+          <!-- responsive horizontal -->
           <ins class="adsbygoogle"
-               style="display:inline-block;width:728px;height:90px"
+               style="display:block"
                data-ad-client="ca-pub-1387152161263228"
-               data-ad-slot="4063266514"></ins>
+               data-ad-slot="6664212987"
+               data-ad-format="auto"></ins>
         </div>
 
         {{ content }}