tidy up series block in collections a little

atlas/templates/atlas/collection_case_view_take.html

@@ -22,6 +22,10 @@
     {% endif %}
 
     <div class="pre-whitespace multi-image-block">
+            <details open>
+            <summary>
+            Images
+            </summary>
         {% for series in series_list %}
             <span class="series-block">
                 <a href="#" onclick='window.loadDicomViewer(window.images[{{forloop.counter0}}])'>
@@ -32,6 +36,7 @@
                 </a>
             </span>
         {% endfor %}
+            </details>
     </div>
 
     <div>
@@ -99,7 +104,7 @@
 
         }
         .series-block {
-            border: darkgray solid 1px;
+            border: darkblue solid 1px;
             padding: 1px;
             text-decoration: none;
             text-align: center;