title: How can I change the font of a PreText or Paragraph widget?
body: <p>I've been trying to change the font of a PreText widget in Python Bokeh, but I failed until now.</p>
  
  <p>I already tried to format the text by using css:</p>
  
  <pre><code>pre = PreText(text="text", width=1000, height=500, 
                style={'font-size':'40pt', 
                       'color': 'grey', 
                       'font-weight': 'bold', 
                       'font-family': 'Arial, Helvetica, sans-serif'})
  </code></pre>
  
  <p>But unfortunatelly everything works but 'font-family' doesn't!</p>