doc: fix root.html styles

R=r
CC=golang-dev
https://golang.org/cl/7442045
diff --git a/doc/root.html b/doc/root.html
index cc2bfd1..34915c0 100644
--- a/doc/root.html
+++ b/doc/root.html
@@ -53,11 +53,11 @@
 <div id="gopher"></div>
 
 <a href="/doc/install" id="start">
-<div class="big">Download Go</div>
-<div class="desc">
+<span class="big">Download Go</span>
+<span class="desc">
 Binary distributions available for<br>
 Linux, Mac OS X, Windows, and more.
-</div>
+</span>
 </a>
 
 </div>
diff --git a/doc/style.css b/doc/style.css
index f4fcf3e..3d881b0 100644
--- a/doc/style.css
+++ b/doc/style.css
@@ -267,10 +267,12 @@
 	border-radius: 5px;
 }
 a#start .big {
+	display: block;
 	font-weight: bold;
 	font-size: 20px;
 }
 a#start .desc {
+	display: block;
 	font-size: 14px;
 	font-weight: normal;
 	margin-top: 5px;