Address review comments

IPython/html/static/base/less/variables.less

@@ -10,6 +10,7 b''
 @modal-inner-padding: 15px;
 @grid-float-breakpoint: 540px;
 @logo_height: 28px;
+@border-radius-base: 2px;
 
 // Disable modal slide-in from top animation.
 .modal {

IPython/html/static/terminal/less/terminal.less

@@ -1,17 +1,14 b''
 .terminal {
   float: left;
-  border: black solid 5px;
   font-family: monospace;
-  font-size: 11px;
   color: white;
   background: black;
-  border-radius: 2px;
+  border-radius: @border-radius-base;
   box-shadow: 0px 4px 11px 0px gray;
-  border: 0px;
   padding: @code_padding;
 
   &, dummy-screen {
-    line-height: @code_line_height;
+    line-height: 1em;
     font-size: @notebook_font_size;
   }
 }

IPython/html/static/tree/less/tree.less

@@ -57,7 +57,7 b' ul.breadcrumb {'
   margin-top: @dashboard_tb_pad;
   margin-bottom: 5*@dashboard_tb_pad;
   border: 1px solid @border_color;
-  border-radius: 4px;
+  border-radius: @border-radius-base;
 }
 
 .list_container > div {