CLDC-4352: update hint text as dropdown

app/models/form/sales/pages/building_height_class.rb

@@ -2,6 +2,7 @@ class Form::Sales::Pages::BuildingHeightClass < ::Form::Page
   def initialize(id, hsh, subsection)
     super
     @id = "building_height_class"
+    @copy_key = "sales.property_information.buildheightclass"
     @depends_on = [
       { "proptype" => 1 },
       { "proptype" => 2 },

app/models/form/sales/questions/building_height_class.rb

@@ -3,6 +3,7 @@ class Form::Sales::Questions::BuildingHeightClass < ::Form::Question
     super
     @id = "buildheightclass"
     @type = "radio"
+    @top_guidance_partial = "building_height_class"
     @answer_options = ANSWER_OPTIONS
     @question_number = get_question_number_from_hash(QUESTION_NUMBER_FROM_YEAR)
   end

app/views/form/guidance/_building_height_class.html.erb

@@ -0,0 +1,5 @@
+<div class="govuk-body">
+  <%= govuk_details(summary_text: I18n.t("forms.#{@log.form.start_date.year}.lettings.guidance.building_height_class.title")) do %>
+    <%= I18n.t("forms.#{@log.form.start_date.year}.lettings.guidance.building_height_class.content").html_safe %>
+  <% end %>
+</div>

config/locales/forms/2026/lettings/guidance.en.yml

@@ -76,3 +76,12 @@ en:
           needs_type:
             title: "What does each need type mean?"
             content: "General needs housing includes both self-contained and shared housing without support or specific adaptations.<br><br>Supported housing is housing with special design facilities or features targeted at a specific client group requiring support, for example housing designed for older people, sheltered accommodation, extra care housing. It can include direct access hostels, group homes, and purpose-built self-contained housing. We do not require CORE logs for residential care or nursing homes."
+
+          building_height_class:
+            title: "What do these classifications mean?"
+            content: "<p>High-rise residential buildings are those containing 2 or more residential units and either:</p>
+                      <ul class=\"govuk-list govuk-list--bullet\">
+                        <li>have 7 or more stories</li>
+                        <li>are at least 18 metres in height</li>
+                      </ul>
+                      <p>If unsure, answer based on the number of storeys.</p>"

config/locales/forms/2026/sales/property_information.en.yml

@@ -60,10 +60,10 @@ en:
             question_text: "What type of unit is the property?"
 
           buildheightclass:
-            page_header: ""
+            page_header: "Building height classification"
             check_answer_label: "Building height classification"
             check_answer_prompt: ""
-            hint_text: "High-rise residential buildings are those containing 2 or more residential units and either have 7 or more storeys or are at least 18 metres in height. If unsure, answer based on the number of storeys."
+            hint_text: ""
             question_text: "What is the building height classification?"
 
           builtype: