Convert almost all variables from sass to css. Move reset into base.

assets/sass/styles.scss

@@ -10,16 +10,12 @@
 
 // Declaring CSS misc variables in :root.
 
-@import 'root';
+@import 'variables';
 
 // Ensure fonts get loaded early to minimize front-end performance impact.
 
 @import 'fonts';
 
-// Reset browsers to some sane defaults.
-
-@import 'reset';
-
 // Base styles.
 
 @import 'base/base';