[MD settings] change button padding and placement

chrome/browser/resources/settings/system_page/system_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://md-settings/controls/settings_checkbox.html">
 <link rel="import" href="chrome://md-settings/prefs/prefs.html">
 <link rel="import" href="chrome://md-settings/settings_shared_css.html">
 <link rel="import" href="chrome://md-settings/system_page/system_page_browser_proxy.html">
 
 <dom-module id="settings-system-page">
   <template>
     <style include="settings-shared">
@@ skipping 18 matching lines @@
         <settings-checkbox label="$i18n{hardwareAccelerationLabel}"
             pref="{{prefs.hardware_acceleration_mode.enabled}}">
         </settings-checkbox>
         <template is="dom-if" if="[[shouldShowRestart_(
             prefs.hardware_acceleration_mode.enabled.value)]]">
           <paper-button on-tap="onRestartTap_">$i18n{restart}</paper-button>
         </template>
       </div>
     </div>
     <div class="settings-box">
-      <div class="button-strip">
-        <paper-button class="primary-button" on-tap="onChangeProxySettingsTap_">
-          $i18n{changeProxySettings}
-        </paper-button>
-      </div>
+      <paper-button class="primary-button" on-tap="onChangeProxySettingsTap_">
+        $i18n{changeProxySettings}
+      </paper-button>
     </div>
   </template>
   <script src="chrome://md-settings/system_page/system_page.js"></script>
 </dom-module>