app/views/search_results/_form.html.erb
<%= form_tag(search_path, method: :get, id: 'search', role: 'form', class: 'mt-3 mb-4') do |f| %>
<div class="row">
<div class="col">
<%= render "search_results/sections/terms" %>
</div>
</div>
<div class="row justify-content-between">
<div class="col">
<%= render "search_results/sections/languages" %>
</div>
<div class="col-auto">
<button class="btn btn-outline-secondary collapse-toggle" data-toggle="collapse" data-target="#detailedSearch" type="button" aria-expanded="false" aria-controls="detailedSearch">
<span class="mr-2"><%= t('txt.views.search_results.detailed_search') %></span>
<i class="hide-if-expanded fa fa-chevron-down"></i>
<i class="hide-if-collapsed fa fa-chevron-up"></i>
</button>
</div>
</div>
<div id="detailedSearch" class="collapse <%= current_user ? 'show' : ''%>">
<%= render 'detailed_search' %>
</div>
<% end %>