make new post view overlay-ish

lms/static/sass/discussion/_discussion.scss

@@ -356,6 +356,7 @@ section.discussion {
 }
 
 .new-post-article {
+
   .inner-wrapper {
     max-width: 1180px;
     min-width: 760px;
@@ -369,6 +370,7 @@ section.discussion {
     color: $gray-d3;
     font-weight: 700;
   }
+
 }
 
 .edit-post-form {

lms/static/sass/discussion/elements/_navigation.scss

@@ -385,7 +385,9 @@
     &:hover,
     &:focus {
         color: $forum-color-active-text;
-        background-color: $forum-color-active-thread;
+        // !important overrides the one set here:
+        // https://github.com/edx/edx-platform/blob/master/lms/static/sass/elements/_controls.scss#L472
+        background-color: $forum-color-active-thread !important;
     }
 }
 

lms/static/sass/discussion/views/_inline.scss

@@ -39,4 +39,25 @@
     .wmd-preview {
         @include discussion-wmd-preview;
     }
+
+   .new-post-article {
+        position: relative;
+        border: 1px solid $forum-color-border;
+
+        .add-post-cancel {
+          @include right($baseline / 2);
+          top: $baseline / 2;
+          position: absolute;
+          color: $uxpl-primary-blue;
+
+            &:hover,
+            &:focus {
+                border-color: transparent;
+                box-shadow: none;
+                background-color: transparent;
+                background-image: none;
+            }
+        }
+    }
+
 }