WIP style adjustments to match eh22 styleguide

css/area_content.less

@@ -4,23 +4,13 @@
 
 .content .row {
     > .col-xs-12 {
-        box-shadow: @box-shadow;
+
+        background-color: var(--color-background);
+
 
         #dokuwiki__content {
             position: relative;
 
-            &::before {
-                content: '';
-                position: absolute;
-                top: 0;
-                left: 0;
-                height: @page-header_height;
-                box-sizing: border-box;
-                width: 100%;
-                background-color: @ini_background_page_header;
-                border-bottom: 1px solid @ini_border_light;
-            }
-
             .page-content {
                 padding-top: @page-header_height;
 
@@ -31,6 +21,11 @@
             }
         }
     }
+    @media @screen_min-md {
+        > .col-xs-12 {
+            border-left: dashed 0.25em var(--color-shade-4);
+        }
+    }
 }
 
 .main-content > .level2,