update preview overview and update images.

Change-Id: Ie4c37f5895e15313cc4dd58ef72a8fcd5ab20189
diff --git a/docs/html/index.jd b/docs/html/index.jd
index e46add9..6066531 100644
--- a/docs/html/index.jd
+++ b/docs/html/index.jd
@@ -18,7 +18,7 @@
 
 <section class="dac-expand dac-hero dac-invert" style="background-color:#455A64">
   <div class="wrap" style="max-width:1100px;margin-top:0">
-    <div class="col-7of16 col-push-9of16">
+    <div class="col-7of16 col-push-9of16" style="padding-left:2em;">
       <a href="{@docRoot}preview/index.html">
         <h1 class="dac-hero-title">Android N Developer Preview</h1>
         <p class="dac-hero-description">
@@ -38,7 +38,7 @@
         </a><br>-->
       </a>
     </div>
-    <div class="col-9of16 col-pull-7of16 dac-hero-figure" style="margin-top:0em;padding-right:2em;">
+    <div class="col-9of16 col-pull-7of16 dac-hero-figure" style="margin-top:0em;padding-right:1.5em;">
       <a href="{@docRoot}preview/index.html">
         <img style="" class="dac-hero-image" src="/images/home/n-preview-hero.png"
              srcset="/images/home/n-preview-hero.png 1x,
@@ -84,7 +84,7 @@
     <div class="actions">
       <div><a href="{@docRoot}sdk/index.html">
         <span class="dac-sprite dac-auto-chevron-large"></span>
-        Get the SDK
+        Get Android Studio
       </a></div>
       <div><a href="{@docRoot}samples/index.html">
         <span class="dac-sprite dac-auto-chevron-large"></span>