syncing up styling for collapse/expand toggle links on step header UI

apps/openassessment/templates/openassessmentblock/self/oa_self_closed.html

 {%  extends "openassessmentblock/self/oa_self_assessment.html" %}
 
 {% block list_item %}
-<li id="openassessment__self-assessment" class="openassessment__steps__step step--self-assessment is--incomplete is--collapsed">
+<li id="openassessment__self-assessment" class="openassessment__steps__step step--self-assessment is--incomplete is--empty is--collapsed">
 {% endblock %}
 
 {% block title %}

apps/openassessment/templates/openassessmentblock/self/oa_self_complete.html

 {%  extends "openassessmentblock/self/oa_self_assessment.html" %}
 
 {% block list_item %}
-<li id="openassessment__self-assessment" class="openassessment__steps__step step--self-assessment is--complete is--collapsed">
+<li id="openassessment__self-assessment" class="openassessment__steps__step step--self-assessment is--complete is--empty is--collapsed">
 {% endblock %}
 
 {% block title %}

apps/openassessment/xblock/static/css/openassessment.css

@@ -1203,6 +1203,15 @@ hr.divider,
     color: white; }
 .openassessment .openassessment__steps__step.has--error .step__label {
   color: #bc5547; }
+.openassessment .ui-toggle-visibility .ui-toggle-visibility__control .step__label {
+  -webkit-transition: color 0.25s ease-in;
+  -moz-transition: color 0.25s ease-in;
+  transition: color 0.25s ease-in;
+  color: #33a6dc; }
+  .openassessment .ui-toggle-visibility .ui-toggle-visibility__control .step__label:hover, .openassessment .ui-toggle-visibility .ui-toggle-visibility__control .step__label:focus {
+    color: #00a7f6; }
+  .openassessment .ui-toggle-visibility .ui-toggle-visibility__control .step__label:active, .openassessment .ui-toggle-visibility .ui-toggle-visibility__control .step__label.is--current {
+    color: #1d9dd9; }
 .openassessment .message {
   margin-bottom: 30px; }
 .openassessment .message--error .message__title {

apps/openassessment/xblock/static/sass/oa/views/_oa-base.scss

@@ -221,7 +221,7 @@
         }
       }
 
-      // STATE: has error
+      // STATE: actions has an error
       &.has--error {
         @include row();
         background: tint($color-error, 90%);
@@ -421,6 +421,24 @@
 
 
   // --------------------
+  // collapse and expand styling for step labels
+  // --------------------
+  // TODO: clean this scope up
+  .ui-toggle-visibility .ui-toggle-visibility__control .step__label {
+    @include transition(color $tmg-f2 ease-in);
+    color: $action-primary-color;
+
+    &:hover, &:focus {
+      color: $action-primary-color-focus;
+    }
+
+    &:active, &.is--current {
+      color: $action-primary-color-active;
+    }
+  }
+
+
+  // --------------------
   // messages
   // --------------------
   .message {