anchor.diff:    <div class="col-1">
       <a class="carousel-control-next" href="#lectureCarousel"
          role="button" data-slide="next"
  -       style="right: 50%; color: black; display: <%= show_controls %>">
  +       style="right: 50%; color: black; top: -8px; width: 100%; display: <%= show_controls %>">
         <i class="material-icons" style="font-size:48px">
           keyboard_arrow_right
         </i>
  
positive.code:   <div class="col-1">
      <a class="carousel-control-prev" href="#lectureCarousel"
         role="button" data-slide="prev"
         style="left: 50%; color: black; display: <%= show_controls %>">
        <i class="material-icons" style="font-size: 48px;">
          keyboard_arrow_left
        </i>
  
negative.code:     </a>
    </div>
  </div>
  <div id="lectureCarousel" class="carousel slide carousel-fade" data-ride="carousel"
       data-interval="false">
    <div class="carousel-inner">
          <% @course.lectures.each_with_index do |l, i| %>
            <div class="carousel-item <%= i == 0 ? 'active' : ''%>"
                 data-term="<%= l.term.to_label %>"
                 data-teacher="<%= l.teacher.name %>">
              <div class="row">
              <% unless l.chapters.empty? %>
              <div class="col-12 col-md-12 col-lg-7 pt-3">
              <%= render partial: 'lectures/content', locals: { lecture: l } %>
              </div>
              <% end %>
              <% unless l.lessons.empty? %>
                <div class="col-12 col-md-12 col-lg-5 pt-3">
                  <%= render partial: 'lessons/lessons',
                             locals: { lessons: l.lessons,
                                       lessons_description: 'Verknüpfte Sitzungen' } %>
                 </div>
              <% end %>
              </div>
              <% unless l.tags.empty? %>
                <div class="row pt-5 pb-3">
                  <div class="col-12">
                    <%= render partial: 'tags/tags_toggle',
                        locals: { tags: l.tags,
                                  tags_description: 'Verknüpfte Begriffe',
                                  id: l.id} %>
                  </div>
                </div>
              <% end %>
            </div>
          <% end %>
    </div>
  </div>
  