Remove SCSS color variables

style.scss

 ---
 ---
-
-/* Variables */
-
-$color-primary: black;
-$color-secondary: white;
-$border-radius: 0.375rem;
-
 /* Mixins */
 
 @mixin for-tablet-up {
@@ -50,24 +43,24 @@ a {
 .button {
   display: inline-block;
   padding: 1rem 1.5rem;
-  border-radius: $border-radius;
+  border-radius: 0.375rem;
   border: 1px solid transparent;
 }
 
 .button-primary {
-  color: $color-secondary;
-  background-color: $color-primary;
+  color: white;
+  background-color: black;
 }
 
 .button-secondary {
-  border-color: $color-primary;
+  border-color: black;
 }
 
 /* Header */
 
 .header {
   padding: 4rem 0;
-  border-bottom: 1px solid $color-primary;
+  border-bottom: 1px solid black;
   text-align: center;
 
   @include for-tablet-up {
@@ -119,6 +112,8 @@ a {
   }
 }
 
+/* Icons */
+
 .feather-icon {
   display: inline-block;
   width: 1.5rem;