Remove code bg from breadcrumbs

src/sentry/static/sentry/less/group-detail.less

@@ -1505,7 +1505,7 @@ ul.crumbs {
     margin: 0;
     border-left: 1px solid transparent;
     border-right: 1px solid transparent;
-    border-bottom: 1px solid lighten(@trim, 6);
+    border-bottom: 1px solid lighten(@trim, 4);
     padding: 6px 20px 3px 60px;
     position: relative;
 
@@ -1635,8 +1635,9 @@ ul.crumbs {
 
       pre {
         display: inline-block;
-        padding: 2px 8px;
-        margin: -1px 0 0;
+        padding: 0;
+        margin-top: 1px;
+        background: none;
       }
     }
 
@@ -1656,20 +1657,32 @@ ul.crumbs {
           content: " ";
           display: block;
           width: 100%;
-          height: 8px;
-          #gradient > .vertical(rgba(255, 255, 255, 0), #ffffff);
+          height: 15px;
+          #gradient > .vertical(rgba(255, 255, 255, 0), rgba(255, 255, 255, 1));
+          z-index: 1;
         }
 
         &:hover {
-          pre {
-            background: @white-darkest;
+          &:before {
+            position: absolute;
+            bottom: 4px;
+            right: 0;
+            font-family: 'sentry-simple';
+            content: "\e617";
+            background: @white-dark;
+            border: 1px solid darken(@trim, 5);
+            border-radius: 3px;
+            box-shadow: 0 1px 3px rgba(0,0,0, .1);
+            z-index: 2;
+            padding: 0 5px;
+            margin-left: -14px;
           }
         }
       }
 
       &.expanded {
         max-height: none;
-        &:after {
+        &:after, &:before {
           display: none;
         }
       }
@@ -1851,10 +1864,6 @@ ul.crumbs {
         border-color: @red-dark;
       }
 
-      pre {
-        background: #F8EEED;
-      }
-
       &:before {
         background: #F1D8D5;
       }