TCA-1260 - FCC: fix sidebar overlap

Author: vas3a

src-ts/tools/learn/free-code-camp/fcc-sidebar/FccSidebar.module.scss

@@ -6,6 +6,7 @@
     left: 0;
     top: 0;
     bottom: 0;
+    z-index: 1;
 
     @include ltemd {
         position: relative;
@@ -29,4 +30,4 @@
     flex: 0 0 auto;
     margin-bottom: $space-xl;
     margin-top: $space-lg;
-}
+}