Kraft radio-buttons, um zu zeigen, inline

Ich bin mit bootstrap-Stil ein Formular mit radio-buttons.

Leider display:inline ist nicht die radio-buttons auf der form-inline. Weder in Bewegung ist display:inline in css.

<div class="row">
  <div class="span6 offset3">   
    <div style="display:inline">
      <%= f.label "status_open", "Open" %>
      <%= f.radio_button :status, 'Open' %> <br />
      <%= f.label "status_active",  "Active" %>
      <%= f.radio_button :status, 'Active' %> <br />
      <%= f.label "status_closed",  "Closed" %>
      <%= f.radio_button :status, 'Closed' %> <br />
      <%= f.label "status_matched", "Matched" %>
      <%= f.radio_button :status, 'Matched' %> <br />   
    </div>      
    <%= f.submit "Submit", class: "btn btn-large btn-primary" %>
    <% end %>
  </div>
</div>

Quelle:

<div class="row">
<div class="span6 offset3">
<form accept-charset="UTF-8" action="/books" class="new_book" id="new_book"   method="post"><div style="margin:0;padding:0;display:inline"></div>

  <label for="book_title">Title</label>
  <input id="book_title" name="book[title]" size="30" type="text" />

  <label for="book_isbn">Isbn</label>
  <input id="book_isbn" name="book[isbn]" size="30" type="text" />

  <label for="book_edition">Edition</label>
  <input id="book_edition" name="book[edition]" size="30" type="text" />

  <label for="book_year">Year</label>
  <input id="book_year" name="book[year]" size="30" type="text" />

  <div style="display:inline">
  <label for="book_book_category_fiction">Fiction</label>
  <input id="book_category_fiction" name="book[category]" type="radio" value="Fiction" />
  <label for="book_book_category_non_fiction">Non-fiction</label>
  <input id="book_category_non-fiction" name="book[category]" type="radio" value="Non-fiction" />
  </div>
  <br />
  <input class="btn btn-large btn-custom-black" name="commit" type="submit" value="Create Book" />
</form>  
</div>
</div>

Irgendwelche Ideen auf, warum die buttons nicht angezeigt werden inline? Irgendwelche Gedanken werden sehr geschätzt.