cucumber.css

body { min-width: 950px; }
.cucumber {
  background: #f4f4f4;
  color: #666;
  padding: 0 2% 1em;
  width: 58%;
}

.cucumber .feature h2 {
  font-size: 2.5em;
  border-bottom: 3px solid #ccc;
  padding: .5em 0;
}

.cucumber .feature p {
  font-size: 2em;
  line-height: 1.5em;
  font-weight: bold;
  color: #aaa;
  font-style: italic;
}

.cucumber .feature p, .cucumber .scenario, .cucumber .background {
  margin-left: 20px;
}

.cucumber .scenario, .cucumber .background {
  background: #eee;
  padding-bottom: 1px;
  margin-bottom: 2em;
  border: 1px solid #ccc;
}

.cucumber .scenario h3, .cucumber .background h3 {
  color: #666;
  padding: 10px;
  font-size: 1.75em;
  border-bottom: 1px solid #ccc;
  background: #e8e8e8;
  margin-bottom: 0;
}

.cucumber .scenario ol, .cucumber .background ol {
  margin-top: 1em;
  margin-left: 10px;
}

.cucumber .scenario li, .cucumber .background li {
  list-style-type: none;
  font-size: 1.375em;
  line-height: 1em;
  padding-left: 0;
  margin-left: .5em;
}

.cucumber .feature li                       { color: #777; }
.cucumber .feature li span                  { font-weight: bold; }
.cucumber .feature li div                   { display: inline-block; }
.cucumber .feature li.passed span.swatch    { background: green; }
.cucumber .feature li.undefined span.swatch { background: yellow; }
.cucumber .feature li.pending span.swatch   { background: yellow; }
.cucumber .feature li.failed span.swatch    { background: red; }
.cucumber .feature li.skipped span.swatch   { background: cyan; }

.cucumber .feature li span.swatch {
  display: inline-block;
  position: relative;
  top: .125em;
  width: 1em;
  height: 1em;
  margin-right: .25em;
}

.cucumber pre {
  border: 1px solid #aaa;
  line-height: 1.375em;
  font-size: 0.9em;
  background: #222;
  padding: 1em;
  margin: .5em 3em .5em 1.75em;
}

.cucumber table {
  border: 1px solid #ccc;
  width: auto;
  margin: 1em 0 0 1em;
}

.cucumber table tr:first-child td {
  font-weight: bold;
  border-bottom: 1px solid #ccc;
}

.toc {
  position: fixed;
  right: 0;
  top: 0;
  height: 100%;
  overflow: auto;
  width: 34%;
  min-width: 300px;
  background: #e9e9e9;
  border-left: 5px solid #ccc;
  padding: 0 2%;
}
.toc h2 {
  padding: .25em 0;
  font-size: 2.5em;
  color: #666;
  margin-bottom: 0;
}

.toc ul { margin: 0; }
.toc li.feature { margin: 0 0 1em 0;}
.toc li.feature:last-child { padding: 0 0 1em 0;}
.toc li.feature > a {
  font-size: 1.5em;
  font-weight: bold;
  padding: .25em .5em;
  display: inline-block;
}

.toc li.scenario {
  padding: .25em 1.5em;
}
.toc li.scenario > a {
  padding: .25em .5em;
  line-height: 1.25em;
}

cucumber.js

(function($) {
  $.fn.outerHTML = function() { return $("<div/>").append(this.eq(0).clone()).html(); };
  $.extend(String.prototype, {
    parameterize: function() {
      return this.replace(/[^\w]+/g, '-').replace(/^\-|\-$/g, '').toLowerCase();
    }
  });

  $(function(){
    // strip out escaped <span>'s
    $(".cucumber .scenario li, .cucumber .background li").each(function(idx, li) {
      var liHTML = $(li).html().replace(/&lt;(\/?span)&gt;/g, "<$1>");
      $(li).html(liHTML);
    });

    $(".cucumber .scenario li, .cucumber .background li").each(function(idx, li) {
      if(!$(li).find("span.swatch").length) {
        $(li).prepend($("<span class='swatch'>"));
      }
    });

    (function() {
      var $ulNavigation = $("<ul>").addClass("reset");
      $(".cucumber .feature").each(function(idx, feature) {
        var $ulScenarios  = $("<ul>"),
            $feature      = $(feature);

        $feature.find(".scenario").each(function(idx2, scenario) {
          var $scenario     = $(scenario),
              scenarioText  = $scenario.find("> :header").text();
          $scenario.find("> :header").attr("id", scenarioText.parameterize());
          $("<li class='scenario'>")
            .append($("<a>")
            .attr("href", "#" + scenarioText.parameterize())
            .text(scenarioText))
            .appendTo($ulScenarios);
        });

        var featureText = $feature.find("> :header").text();
        $feature.find("> :header").attr("id", featureText.parameterize());

        $("<li class='feature'>")
          .append(
            $("<a>")
              .attr("href", "#" + featureText.parameterize())
              .text(featureText)
          )
          .append($ulScenarios)
          .appendTo($ulNavigation);
      });
      $("<div class='toc'>")
        .append($("<h2>Feature Navigation</h2>"))
        .append($ulNavigation)
        .appendTo("body");
    })();
  });
})(jQuery);

file_ext.rb

class File
  def self.string_to_file(string, path)
    directory = File.dirname(path)
    FileUtils.mkdir_p directory unless File.directory?(directory)
    File.open(path, 'w') { |f| f << string }
  end

  def self.path_to_string(path)
    File.new(path).read
  end
end

gistfile3.rb

namespace :cucumber do
  desc "Generates Cucumber results as an HTML file"
  task :generate_html => :environment do
    cucumber_output_path = File.join(RAILS_ROOT, "public", "cucumber.html")
    system("cucumber -p html_output > #{cucumber_output_path}")
    puts "Output Cucumber to public/cucumber.html"
    doc = Hpricot.parse(File.path_to_string(cucumber_output_path))
    puts "Parsing cucumber.html"
    doc.search("html head style:last") do |style|
      style.after %{
        <link href="/stylesheets/reset.css" media="screen" rel="stylesheet" type="text/css" />
        <link href="/stylesheets/forms.css" media="screen" rel="stylesheet" type="text/css" />
        <link href="/stylesheets/extras.css" media="screen" rel="stylesheet" type="text/css" />
        <link href="/stylesheets/screen.css" media="screen" rel="stylesheet" type="text/css" />
        <link href="/stylesheets/admin.css" media="screen" rel="stylesheet" type="text/css" />
        <link href="/stylesheets/cucumber.css" media="screen" rel="stylesheet" type="text/css" />
        <script src="/javascripts/jquery-1.3.2.min.js" type="text/javascript"></script>
        <script src="/javascripts/cucumber.js" type="text/javascript"></script>
      }
    end
    puts "Saving cucumber.html"
    File.string_to_file(doc.to_html, cucumber_output_path)
  end
end