title: why in a django app my css file in the browser sources is empty?
body: <ol>
  <li><p>I have build a web application (using Django).</p></li>
  <li><p>in the settings.py:</p>
  
  <pre><code>STATIC_ROOT=os.path.join(BASE_DIR,"static_in_pro","static_root")
  STATIC_DIRS=os.path.join(BASE_DIR,"static_in_pro","our_static")
  STATICFILES_FINDERS=["django.contrib.staticfiles.finders.FileSystemFinder",
  "django.contrib.staticfiles.finders.AppDirectoriesFinder"]
  </code></pre></li>
  <li><p>in my template <code>base.html</code>:</p>
  
  <pre><code>link href="{% static 'css/main.css'%}" rel="stylesheet"
  link href="{% static 'css/navbar-static-top.css'%}" rel="stylesheet"
  </code></pre></li>
  <li><p>when i use "collectstatic", all static files are copied correctly.</p></li>
  <li>but when i runserver, it doesnt apply statics, actualy the main.css in the browser sources is empty!
  what is the problem?</li>
  </ol>