Get ruthless with the component guide styles

- put all the component sass back into the component guide styles
- create a new print stylesheet for the guide, containing all the component print styles
- remove the application stylesheet from the guide
- this removes all duplication of styles from the component guide and ensures that all components render correctly
- however it does mean the guide doesn't include the application styles, which would be useful for spotting conflicts/override problems, but the alternative wasn't working

app/assets/stylesheets/component_guide/application.scss

@@ -7,6 +7,8 @@
 @import "govuk/helpers/all";
 @import "govuk/core/all";
 
+@import "govuk_publishing_components/all_components";
+
 $gem-guide-border-width: 1px;
 
 .component-list {

app/assets/stylesheets/component_guide/print.scss

@@ -0,0 +1 @@
+@import "govuk_publishing_components/all_components_print";

app/views/layouts/govuk_publishing_components/application.html.erb

@@ -16,12 +16,8 @@
     <%= csrf_meta_tags %>
     <%= favicon_link_tag "govuk_publishing_components/favicon-production.png" %>
 
-    <%= stylesheet_link_tag "#{GovukPublishingComponents::Config.application_stylesheet}" %>
     <%= stylesheet_link_tag "component_guide/application", media: "screen" %>
-
-    <% if GovukPublishingComponents::Config.application_print_stylesheet %>
-      <%= stylesheet_link_tag "#{GovukPublishingComponents::Config.application_print_stylesheet}", media: "print" %>
-    <% end %>
+    <%= stylesheet_link_tag "component_guide/print", media: "print" %>
 
     <%= javascript_include_tag "govuk_publishing_components/vendor/modernizr" %>
     <%= yield :extra_headers %>

config/initializers/assets.rb

@@ -6,6 +6,7 @@
   component_guide/application.js
   component_guide/filter-components.js
   component_guide/visual-regression.js
+  component_guide/print.css
   govuk_publishing_components/all_components.js
   govuk_publishing_components/modules.js
   govuk_publishing_components/vendor/modernizr.js

spec/component_guide/component_index_spec.rb

@@ -34,12 +34,12 @@
   it "includes component guide styles and scripts" do
     visit "/component-guide"
     expect(page).to have_selector('link[href*="/assets/component_guide/application"]', visible: false)
+    expect(page).to have_selector('link[href*="/assets/component_guide/print"]', visible: false)
     expect(page).to have_selector('script[src*="/assets/component_guide/application"]', visible: false)
   end
 
-  it "includes the application’s styles and scripts" do
+  it "includes the application’s scripts" do
     visit "/component-guide"
-    expect(page).to have_selector('link[href*="/assets/application"]', visible: false)
     expect(page).to have_selector('script[src*="/assets/application"]', visible: false)
   end