Refactor glitch header SCSS, modify animation logic w/ sessionStorage

Also fix Sass plugin configuration, re-enable CSS compression

_config.yml

@@ -19,6 +19,7 @@ exclude:
     - LICENSE
 sass:
   style: compressed
+  sourcemap: development
 compress_html:
   ignore:
     envs: ["development"]
@@ -29,6 +30,4 @@ defaults:
     scope:
       path: "_pages"
     values:
-      permalink: "/:title:output_ext"
-sass:
-  sourcemap: development
+      permalink: "/:title:output_ext"