Integrate code review feedback

* Updates mitlibraries-theme gem to v1.4 to use `_skip_links` partial
* Adds `.skip-link` CSS rules (copied form `#skip` rules in style guide)
* Removes `width: 0` rule to support Safari
* Changes color of skip links on focus to white (this didn't come up
during code review, but WAVE flags the blue-on-black as a contrast error)

Author: jazairi

Gemfile

@@ -9,7 +9,7 @@ gem 'graphql-client'
 gem 'http'
 gem 'importmap-rails'
 gem 'jbuilder'
-gem 'mitlibraries-theme', git: 'https://github.com/mitlibraries/mitlibraries-theme', tag: 'v1.2'
+gem 'mitlibraries-theme', git: 'https://github.com/mitlibraries/mitlibraries-theme', tag: 'v1.4'
 gem 'puma'
 gem 'rails', '~> 7.0'
 gem 'sentry-rails'

Gemfile.lock

@@ -1,7 +1,7 @@
 GIT
   remote: https://github.com/mitlibraries/mitlibraries-theme
-  revision: bcbe5d3de36a92d275085a045c5c4d8f30f33e62
-  tag: v1.2
+  revision: ba5bdc9840ef817ba0b92e522b92da3f52669fc3
+  tag: v1.4
   specs:
     mitlibraries-theme (1.0.2)
       rails (>= 6, < 8)

app/assets/stylesheets/partials/_shared.scss

@@ -39,3 +39,23 @@
     }
   }
 }
+
+.skip-link {
+  position: absolute;
+  overflow: hidden;
+  top: 0;
+  left: 0;
+  height: 0;
+  color: $gray-l2;
+  background-color: $black;
+  border-bottom: 2px solid $success;
+
+  &:focus {
+    position: relative;
+    display: block;
+    height: auto;
+    color: $white;
+    width: 100%;
+    padding: 5px 2%;
+  }
+}

app/views/layouts/_skip_links.html.erb

@@ -0,0 +1,11 @@
+<a class="skip-link sr sr-focusable" href="#main-menu">Skip to main menu</a>
+<a class="skip-link sr sr-focusable" href="#basic-search">Skip to search form</a>
+<% if current_page?(results_path) %>
+  <a class="skip-link sr sr-focusable" href="#results">Skip to results</a>
+  <% if @filters.present? %>
+    <a class="skip-link sr sr-focusable" href="#filters">Skip to search filters</a>
+  <% end %>
+<% end %>
+<% if controller.controller_name == 'record' && controller.action_name == 'view' %>
+  <a class="skip-link sr sr-focusable" href="#full-record">Skip to metadata</a>
+<% end %>