diff --git a/Orange/canvas/__main__.py b/Orange/canvas/__main__.py
index 9a6abbc1c4b..815e95a4034 100644
--- a/Orange/canvas/__main__.py
+++ b/Orange/canvas/__main__.py
@@ -573,6 +573,9 @@ def onrequest(url):
 
                 stylesheet_string = pattern.sub("", stylesheet_string)
 
+                if 'dark' in stylesheet:
+                    app.setProperty('darkMode', True)
+
             else:
                 log.info("%r style sheet not found.", stylesheet)
 
diff --git a/Orange/widgets/data/__init__.py b/Orange/widgets/data/__init__.py
index 26a3816dc4c..5e3c3862d8e 100644
--- a/Orange/widgets/data/__init__.py
+++ b/Orange/widgets/data/__init__.py
@@ -1,3 +1,4 @@
+
 NAME = "Data"
 
 ID = "orange.widgets.data"
@@ -12,6 +13,15 @@
 
 ICON = "icons/Category-Data.svg"
 
-BACKGROUND = "#FFD39F"
+from AnyQt.QtGui import QPalette
+
+BACKGROUND = {
+    'light': {
+        QPalette.Light: '#febc57',
+        QPalette.Midlight: '#fe9457',
+        QPalette.Button: '#fe9057',
+    },
+    'plain': "#FFD39F",
+}
 
 PRIORITY = 1
diff --git a/Orange/widgets/evaluate/__init__.py b/Orange/widgets/evaluate/__init__.py
index b19110dba1e..38c479dc53f 100644
--- a/Orange/widgets/evaluate/__init__.py
+++ b/Orange/widgets/evaluate/__init__.py
@@ -2,11 +2,21 @@
 Widgets from Evaluate category
 
 """
+
 NAME = "Evaluate"
 
 DESCRIPTION = "Evaluate classification/regression performance."
 
-BACKGROUND = "#C3F3F3"
+from AnyQt.QtGui import QPalette
+
+BACKGROUND = {
+    'light': {
+        QPalette.Light: '#a5ebeb',
+        QPalette.Midlight: '#5cebeb',
+        QPalette.Button: '#4be3f2',
+    },
+    'plain': "#C3F3F3",
+}
 
 ICON = "icons/Category-Evaluate.svg"
 
diff --git a/Orange/widgets/model/__init__.py b/Orange/widgets/model/__init__.py
index d43d24dd36d..5693e3f8cdb 100644
--- a/Orange/widgets/model/__init__.py
+++ b/Orange/widgets/model/__init__.py
@@ -4,7 +4,16 @@
 
 DESCRIPTION = 'Prediction.'
 
-BACKGROUND = '#FAC1D9'
+from AnyQt.QtGui import QPalette
+
+BACKGROUND = {
+    'light': {
+        QPalette.Light: '#ffbddb',
+        QPalette.Midlight: '#ff8dc6',
+        QPalette.Button: '#f175b6',
+    },
+    'plain': "#FAC1D9",
+}
 
 ICON = 'icons/Category-Model.svg'
 
diff --git a/Orange/widgets/unsupervised/__init__.py b/Orange/widgets/unsupervised/__init__.py
index 912138e530e..f8c4cb96834 100644
--- a/Orange/widgets/unsupervised/__init__.py
+++ b/Orange/widgets/unsupervised/__init__.py
@@ -13,7 +13,16 @@
 
 DESCRIPTION = "Unsupervised learning."
 
-BACKGROUND = "#CAE1EF"
+from AnyQt.QtGui import QPalette
+
+BACKGROUND = {
+    'light': {
+        QPalette.Light: '#aed2d9',
+        QPalette.Midlight: '#5abced',
+        QPalette.Button: '#499fd8',
+    },
+    'plain': "#CAE1EF",
+}
 
 ICON = "icons/Category-Unsupervised.svg"
 
diff --git a/Orange/widgets/visualize/__init__.py b/Orange/widgets/visualize/__init__.py
index ff3394c681d..547405a34c0 100644
--- a/Orange/widgets/visualize/__init__.py
+++ b/Orange/widgets/visualize/__init__.py
@@ -15,7 +15,16 @@
 
 DESCRIPTION = "Widgets for data visualization."
 
-BACKGROUND = "#FFB7B1"
+from AnyQt.QtGui import QPalette
+
+BACKGROUND = {
+    'light': {
+        QPalette.Light: '#f2b6b8',
+        QPalette.Midlight: '#ff8a99',
+        QPalette.Button: '#ff7a8a',
+    },
+    'plain': "#FFB7B1",
+}
 
 ICON = "icons/Category-Visualize.svg"
 
diff --git a/Orange/widgets/visualize/owscatterplotgraph.py b/Orange/widgets/visualize/owscatterplotgraph.py
index 1110a44393e..d3f28db9854 100644
--- a/Orange/widgets/visualize/owscatterplotgraph.py
+++ b/Orange/widgets/visualize/owscatterplotgraph.py
@@ -8,7 +8,7 @@
 
 import numpy as np
 from AnyQt.QtCore import Qt, QRectF, QSize, QTimer, pyqtSignal as Signal, \
-    QObject
+    QObject, QEvent
 from AnyQt.QtGui import QColor, QPen, QBrush, QPainterPath, QTransform, \
     QPainter
 from AnyQt.QtWidgets import QApplication, QToolTip, QGraphicsTextItem, \
@@ -568,8 +568,7 @@ def __init__(self, scatter_widget, parent=None, view_box=ViewBox):
 
         self.view_box = view_box(self)
         _axis = {"left": AxisItem("left"), "bottom": AxisItem("bottom")}
-        self.plot_widget = pg.PlotWidget(viewBox=self.view_box, parent=parent,
-                                         background="w", axisItems=_axis)
+        self.plot_widget = pg.PlotWidget(viewBox=self.view_box, parent=parent, axisItems=_axis)
         self.plot_widget.hideAxis("left")
         self.plot_widget.hideAxis("bottom")
         self.plot_widget.getPlotItem().buttonsHidden = True
diff --git a/Orange/widgets/visualize/utils/widget.py b/Orange/widgets/visualize/utils/widget.py
index 0f00929e0ad..c59478a109f 100644
--- a/Orange/widgets/visualize/utils/widget.py
+++ b/Orange/widgets/visualize/utils/widget.py
@@ -2,10 +2,12 @@
 
 import numpy as np
 
-from AnyQt.QtCore import QSize, Signal
+from AnyQt.QtCore import QSize, Signal, QEvent, Qt
 from AnyQt.QtWidgets import QApplication
+from PyQt5.QtGui import QPalette, QPen
 
 from orangewidget.utils.visual_settings_dlg import VisualSettingsDialog
+from pyqtgraph import AxisItem
 
 from Orange.data import (
     Table, ContinuousVariable, Domain, Variable, StringVariable
@@ -412,6 +414,7 @@ def __init__(self):
     def setup_gui(self):
         self._add_graph()
         self._add_controls()
+        # self._update_palette()
         self.input_changed.emit(None)
         self.output_changed.emit(None)
 
@@ -663,6 +666,29 @@ def onDeleteWidget(self):
         self.graph.plot_widget.clear()
         self.graph.clear()
 
+    # def changeEvent(self, event):
+    #     if event.type() == QEvent.PaletteChange:
+    #         self._update_palette()
+    #     super().changeEvent(event)
+    #
+    # def _update_palette(self):
+    #     palette: QPalette = self.palette()
+    #     brush = palette.base()
+    #     text_color = palette.color(QPalette.WindowText)
+    #
+    #     self.graph.update_colors()  # TODO?
+    #     self.graph.plot_widget.setBackground(brush)
+    #     self.graph.tip_textitem.setDefaultTextColor(Qt.black)
+    #
+    #     pen = QPen(text_color)
+    #
+    #     plotItem = self.graph.plot_widget.plotItem
+    #     plotItem.titleLabel.setText(brush.color().name())
+    #     for name in plotItem.axes:
+    #         a: AxisItem = plotItem.getAxis(name)
+    #         a.setPen(pen)
+    #         a.setTextPen(pen)
+
 
 class OWAnchorProjectionWidget(OWDataProjectionWidget, openclass=True):
     """ Base widget for widgets with graphs with anchors. """