NNTP: Fix the issue where the lower corners had a fex dark pixels...

chrome/browser/resources/new_new_tab.css

 html {
   /* This is needed because of chrome://theme/css/new_tab.css */
   height: 100%;
 }
 
 body {
   margin: 0;
 }
 
 #main {
@@ skipping 220 matching lines @@
   padding: 1px;
   -webkit-border-radius: 5px;
   display: block;
   -webkit-box-shadow: 0px 2px 2px hsla(0, 0%, 0%, 0);
   -webkit-transition: width .15s, height .15s, border-color .15s,
       -webkit-border-radius .15s, -webkit-box-shadow .15s;
 }
 
 .edit-mode-border {
   -webkit-border-radius: 4px;
-  background-color: hsla(213, 54%, 95%, 0);
 
   /* when dragged over we move this */
   position: relative;
   -webkit-transition: top .15s, left .15s;
 }
 
 .thumbnail-container:focus .thumbnail,
 .thumbnail-container:hover .thumbnail {
   border-color: hsl(213, 66%, 57%);
   -webkit-box-shadow: 0px 2px 2px hsla(0, 0%, 0%, 0);
@@ skipping 496 matching lines @@
   #t3, #t7,
   html[dir='rtl'] #t0,
   html[dir='rtl'] #t4 {
     left: 534px;
   }
 
   #t4, #t5, #t6, #t7 {
     top: 147px;
   }
 }