dom-ui settings: Tweak 'text-button' css to not conflict with 'button' customizations.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/6386001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72213 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/options/options_page.css

@@ -354,9 +354,14 @@ label.radio {
   text-decoration: underline;
 }
 
-.text-button {
-  background-color: transparent;
+.text-button,
+.text-button:active,
+.text-button:focus,
+.text-button:hover {
+  -webkit-box-shadow: none;
+  background: transparent none;
   border-color: transparent;
+  color: #000;
 }
 
 .settings-list {