Can't apply CSS stylesheet to Wufoo form in Unbounce

Question

I have a Wufoo form inside an Unbounce landing page, and I'm trying to apply custom styling to the Wufoo form using a custom stylesheet. However, when I publish my changes, the stylesheet doesn't change the appearance of the form.

The form's HTML is generated by a javascript snippet inserted into the landing page, and the CSS stylesheet is nothing fancy (like, styling h2 tags and stuff, very beginner stuff).

Has anyone encountered this problem and/or knows how to solve it? Thanks!

EDIT: Here is the Javascript snippet that Wufoo uses -

var zzzzzz000000;
(function(d, t) {
  var s = d.createElement(t),
    options = {
      'userName': 'xxxxx',
      'formHash': 'yyyyy',
      'autoResize': true,
      'height': '483',
      'async': true,
      'host': 'wufoo.com',
      'header': 'show',
      'ssl': true
    };
  s.src = ('https:' == d.location.protocol ? 'https://' : 'http://') + 'www.wufoo.com/scripts/embed/form.js';
  s.onload = s.onreadystatechange = function() {
    var rs = this.readyState;
    if (rs)
      if (rs != 'complete')
        if (rs != 'loaded') return;
    try {
      zzzzzz000000 = new WufooForm();
      zzzzzz000000.initialize(options);
      zzzzzz000000.display();
    } catch (e) {}
  };
  var scr = d.getElementsByTagName(t)[0],
    par = scr.parentNode;
  par.insertBefore(s, scr);
})(document, 'script');