diff --git a/demo/moulinrouge/__init__.py b/demo/moulinrouge/__init__.py
index 0f29553..be91b69 100644
--- a/demo/moulinrouge/__init__.py
+++ b/demo/moulinrouge/__init__.py
@@ -96,7 +96,7 @@ def create_app():
 
     @app.route("/sparkline/<style>")
     def sparkline(style):
-        line = pygal.Line(style=styles[style])
+        line = pygal.Line(style=styles[style], pretty_print=True)
         line.add('_', [random.randrange(0, 10) for _ in range(25)])
         return Response(
             line.render_sparkline(height=40), mimetype='image/svg+xml')
diff --git a/demo/moulinrouge/tests.py b/demo/moulinrouge/tests.py
index 4cd17f8..0f9915d 100644
--- a/demo/moulinrouge/tests.py
+++ b/demo/moulinrouge/tests.py
@@ -26,14 +26,14 @@ def get_test_routes(app):
     @app.route('/test/bar_links')
     def test_bar_links():
         bar = Bar(style=styles['neon'])
-        # bar.js = ('http://l:2343/svg.jquery.js',
-                  # 'http://l:2343/pygal-tooltips.js')
+        bar.js = ('http://l:2343/svg.jquery.js',
+                  'http://l:2343/pygal-tooltips.js')
         bar.add('1234', [
             {'value': 10,
              'label': 'Ten',
              'xlink': 'http://google.com?q=10'},
             {'value': 20,
-             'label': 'Twenty',
+             'tooltip': 'Twenty',
              'xlink': 'http://google.com?q=20'},
             30,
             {'value': 40,
@@ -117,7 +117,6 @@ def get_test_routes(app):
     def test_dot():
         dot = Dot()
         dot.x_labels = map(str, range(4))
-
         dot.add('a', [1, lnk(3, 'Foo'), 5, 3])
         dot.add('b', [2, 2, 0, 2])
         dot.add('c', [5, 1, 5, lnk(3, 'Bar')])
diff --git a/pygal/config.py b/pygal/config.py
index a3e6b08..3788f4d 100644
--- a/pygal/config.py
+++ b/pygal/config.py
@@ -149,6 +149,8 @@ class Config(object):
         20, int, "Look",
         "Margin around chart")
 
+    tooltip_border_radius = Key(0, int, "Look", "Tooltip border radius")
+
     ############ Label ############
     x_labels = Key(
         None, list, "Label",
@@ -235,7 +237,7 @@ class Config(object):
 
     value_font_size = Key(8, int, "Text", "Value font size")
 
-    tooltip_font_size = Key(20, int, "Text", "Tooltip font size")
+    tooltip_font_size = Key(16, int, "Text", "Tooltip font size")
 
     title_font_size = Key(16, int, "Text", "Title font size")
 
diff --git a/pygal/css/base.css b/pygal/css/base.css
index a1ccfb0..86c95db 100644
--- a/pygal/css/base.css
+++ b/pygal/css/base.css
@@ -18,7 +18,7 @@
  * along with pygal. If not, see <http://www.gnu.org/licenses/>.
 */
 
-/* 
+/*
  * Font-sizes from config, override with care
  */
 
diff --git a/pygal/css/style.css b/pygal/css/style.css
index 38f0192..5c5abd3 100644
--- a/pygal/css/style.css
+++ b/pygal/css/style.css
@@ -18,7 +18,7 @@
  * along with pygal. If not, see <http://www.gnu.org/licenses/>.
 */
 
-/* 
+/*
  * Styles from config
  */
 
diff --git a/pygal/graph/dot.py b/pygal/graph/dot.py
index 77a3c81..db0fd42 100644
--- a/pygal/graph/dot.py
+++ b/pygal/graph/dot.py
@@ -52,7 +52,7 @@ class Dot(Graph):
             self.svg.node(dots, 'circle', cx=x, cy=y, r=size,
                           class_='dot reactive tooltip-trigger')
 
-            self._tooltip_data(dots, value, x, y)
+            self._tooltip_data(dots, value, x, y, classes='centered')
             self._static_value(serie_node, value, x, y)
 
     def _compute(self):
diff --git a/pygal/graph/graph.py b/pygal/graph/graph.py
index 860e14e..04f8db8 100644
--- a/pygal/graph/graph.py
+++ b/pygal/graph/graph.py
@@ -109,7 +109,9 @@ class Graph(BaseGraph):
         a = self.svg.node(self.nodes['tooltip'], 'a')
         self.svg.node(a, 'rect',
                       id="tooltip-box",
-                      rx=5, ry=5, width=0, height=0)
+                      rx=self.tooltip_border_radius,
+                      ry=self.tooltip_border_radius,
+                      width=0, height=0)
         text = self.svg.node(a, 'text', class_='text')
         self.svg.node(text, 'tspan', class_='label')
         self.svg.node(text, 'tspan', class_='value')
diff --git a/pygal/style.py b/pygal/style.py
index 2550f3f..6bf3dab 100644
--- a/pygal/style.py
+++ b/pygal/style.py
@@ -19,7 +19,30 @@
 """
 Charts styling
 """
+from __future__ import division
 from pygal.util import cycle_fill
+from colorsys import rgb_to_hls, hls_to_rgb
+
+
+def darken(color, percent):
+    assert color[0] == '#', '#rrggbb and #rgb format are supported'
+    color = color[1:]
+    assert len(color) in (3, 6), '#rrggbb and #rgb format are supported'
+    if len(color) == 3:
+        color = [a for b in zip(color, color) for a in b]
+
+    return '#%02x%02x%02x' % tuple(
+        map(lambda x: 255 * x,
+            hls_to_rgb(*(
+                lambda h, l, s: (h, max(0, min(1, l - percent / 100)), s))(
+                    *rgb_to_hls(*map(
+                        lambda x: int(''.join(x), 16) / 255,
+                        zip(color[::2], color[1::2])))
+                ))))
+
+
+def lighten(color, percent):
+    return darken(color, -percent)
 
 
 class Style(object):
diff --git a/pygal/svg.py b/pygal/svg.py
index 927d868..d4af653 100644
--- a/pygal/svg.py
+++ b/pygal/svg.py
@@ -60,6 +60,7 @@ class Svg(object):
 
     def add_styles(self):
         """Add the css to the svg"""
+        all_css = []
         for css in ['base.css'] + list(self.graph.css):
             if urlparse(css).scheme:
                 self.processing_instructions.append(
@@ -76,8 +77,9 @@ class Svg(object):
                         font_sizes=self.graph.font_sizes())
                     if not self.graph.pretty_print:
                         css_text = minify_css(css_text)
-                    self.node(
-                        self.defs, 'style', type='text/css').text = css_text
+                all_css.append(css_text)
+        self.node(
+            self.defs, 'style', type='text/css').text = '\n'.join(all_css)
 
     def add_scripts(self):
         """Add the js to the svg"""
diff --git a/pygal/test/test_style.py b/pygal/test/test_style.py
index 73f0650..5048aee 100644
--- a/pygal/test/test_style.py
+++ b/pygal/test/test_style.py
@@ -16,7 +16,7 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with pygal. If not, see <http://www.gnu.org/licenses/>.
-from pygal.style import Style
+from pygal.style import Style, darken, lighten
 
 
 def test_colors():
@@ -102,3 +102,21 @@ def test_colors():
   fill: rgb(12, 231, 3);
 }
 '''
+
+
+def test_darken():
+    assert darken('#800', 20) == '#220000'
+    assert darken('#ffffff', 10) == '#e6e6e6'
+    assert darken('#f3148a', 25) == '#810747'
+    assert darken('#121212', 1) == '#0f0f0f'
+    assert darken('#999999', 100) == '#000000'
+    assert darken('#1479ac', 8) == '#105f87'
+
+
+def test_lighten():
+    assert lighten('#800', 20) == '#ee0000'
+    assert lighten('#ffffff', 10) == '#ffffff'
+    assert lighten('#f3148a', 25) == '#f98dc6'
+    assert lighten('#121212', 1) == '#151515'
+    assert lighten('#999999', 100) == '#ffffff'
+    assert lighten('#1479ac', 8) == '#1893d1'