prefix category name with 'category-banner-' to avoid class collision

prefix category name with ‘category-banner-’ to avoid class collision

diff --git a/common/header.html b/common/header.html
index 97dc5c1..bc41316 100644
--- a/common/header.html
+++ b/common/header.html
@@ -37,7 +37,7 @@
                       }
                   }
 
-                  return h('div.category-title-header' + " ." + category.slug, {
+                  return h('div.category-title-header' + " .category-banner-" + category.slug, {
                       "attributes" : {
                           "style" : "background-color: #" + category.color + "; color: #" + category.text_color + ";"
                       }

GitHub sha: c3bf66fa