Remove unused colors from color palette

The color palette has been stripped down to a
maximum of two colors shades per palette. This
works for our design since components use a
base color with a lighter color as an accent
color. This change reduces the amount of CSS
generated by Bootstrap when the CSS is compiled.

Github Story: https://github.com/openbmc/webui-vue/issues/2

Signed-off-by: Derick Montague <derick.montague@ibm.com>
Change-Id: I2ddb37f5c89c749a7303799c6f7499ddd83d5a92
diff --git a/src/components/AppHeader/AppHeader.vue b/src/components/AppHeader/AppHeader.vue
index aa8d9f8..08c8256 100644
--- a/src/components/AppHeader/AppHeader.vue
+++ b/src/components/AppHeader/AppHeader.vue
@@ -157,7 +157,7 @@
 }
 
 .nav-trigger {
-  fill: $white;
+  fill: $light;
   width: $header-height;
   height: $header-height;
   transition: none;
@@ -167,8 +167,8 @@
   }
 
   &:hover {
-    fill: $white;
-    background-color: $gray-900;
+    fill: $light;
+    background-color: $dark;
   }
 
   @include media-breakpoint-up($responsive-layout-bp) {