Supervised User interstitial: Update strings to be more child-friendly

components/supervised_user_error_page/resources/supervised_user_block_interstitial.css

 /* 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. */
 body {
   background-color: rgb(247, 247, 247);
   font-size: 10pt;
   margin: 150px 60px 0 30px;
 }
 
 #main-frame-blocked {
   margin: auto;
   max-width: 600px;
   min-width: 200px;
 }
 
 h1 {
   font-size: 1.8em;
   font-weight: normal;
   margin: 5px 0 25px 0;
 }
 
+#block-page-message {
+  color: rgb(97,97,97);
+  font-size: 0.667em;
+  margin-top: 16px;
+}
+
 .avatar-img {
   -webkit-user-select: none;
   border: 3px solid rgb(251, 251, 251);
   border-radius: 50%;
   content: -webkit-image-set(
       url(default_100_percent/logo_avatar_circle_blue_color.png) 1x,
       url(default_200_percent/logo_avatar_circle_blue_color.png) 2x);
   margin-bottom: 5px;
   margin-right: 15px;
   margin-top: 5px;
@@ skipping 29 matching lines @@
   background-color: rgb(25,118,210);
   box-shadow: 0 8px 17px 0 rgba(0, 0, 0, 0.2);
   transition-delay: 0s;
 }
 
 #details-button-container {
   color: rgb(97,97,97);
   cursor: pointer;
   display: inline;
   font-size: 12px;
-  text-decoration: underline;
 }
 
 #button-container {
   align-items: baseline;
   display: flex;
   justify-content: space-between;
   margin-top: 60px;
 }
 
 #details {
@@ skipping 27 matching lines @@
     flex-flow: column;
     justify-content: flex-start;
     order: 2;
     text-transform: uppercase;
   }
 
   #details-button-container {
     font-weight: bold;
     margin: auto;
     order: 2;
+    padding: 0 15px;
+    text-align: center;
+    width: 100%;
   }
 
   #request-access-button {
     margin-bottom: 30px;
     order: 1;
-    text-align: center
-  }
-
-  .button {
+    text-align: center;
     width: 100%;
   }
 
   #details {
     margin: auto;
     order: 1;
   }
 
   .hidden-on-mobile {
     display: none;
   }
 
   #main-frame-blocked {
     display: flex;
     flex-flow: column;
   }
 
   #feedback {
     margin-top: 35px;
   }
 }