Aesthetic tweaks to sheriff-o-matic.

Tools/GardeningServer/ui/ct-failure-stream.html

 <!--
 Copyright 2014 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <link rel="import" href="ct-failure-card.html">
 
 <polymer-element name="ct-failure-stream" attributes="groups commitLog tree category title" noscript>
   <template>
     <style>
       :host {
         display: block;
       }
 
       ct-failure-card {
-        margin-bottom: 5px;
-        padding: 5px;
+        padding: 15px 5px;
         border-bottom: 1px solid lightgrey;
       }
 
       /* FIXME: Don't use before hax to add labels */
       ct-failure-card:first-of-type::before {
         content: "{{ title }}:";
         display: block;
         font-weight: bold;
         font-size: 18px;
         padding: 5px;
         background-color: #f5f5f5;
         margin-bottom: 5px;
       }
     </style>
     <template repeat="{{ group in groups }}">
       <template if="{{ group.category == category }}">
         <ct-failure-card group="{{ group }}" commitLog="{{ commitLog }}" tree="{{ tree }}"></ct-failure-card>
       </template>
     </template>
   </template>
 </polymer-element>