Increase pager handle size.

IPython/html/static/notebook/less/pager.less

@@ -7,7 +7,7 b' div#pager {'
     position: fixed;
     bottom: 0px;
     width: 100%;
-    border-top: 1px solid @navbar-default-border;
+    border-top: 4px solid @navbar-default-border;
     max-height: 50%;
 
     /* Display over codemirror */
@@ -42,4 +42,7 b' div#pager {'
         }
     }
 
+    .ui-resizable-handle {
+        top: 0px;
+    }
 }

IPython/html/static/style/style.min.css

@@ -10288,7 +10288,7 b' div#pager {'
   position: fixed;
   bottom: 0px;
   width: 100%;
-  border-top: 1px solid #e7e7e7;
+  border-top: 4px solid #e7e7e7;
   max-height: 50%;
   /* Display over codemirror */
   z-index: 100;
@@ -10319,6 +10319,9 b' div#pager #pager-contents #pager-container {'
   -moz-box-sizing: border-box;
   -webkit-box-sizing: border-box;
 }
+div#pager .ui-resizable-handle {
+  top: 0px;
+}
 .quickhelp {
   /* Old browsers */
   display: -webkit-box;