Allow to configure accent colors

src/pretix/control/forms/organizer.py

@@ -10,7 +10,9 @@ from pretix.api.models import WebHook
 from pretix.api.webhooks import get_all_webhook_events
 from pretix.base.forms import I18nModelForm, SettingsForm
 from pretix.base.models import Device, Organizer, Team
-from pretix.control.forms import ExtFileField, MultipleLanguagesWidget
+from pretix.control.forms import (
+    ColorContrastValidator, ExtFileField, MultipleLanguagesWidget,
+)
 from pretix.multidomain.models import KnownDomain
 from pretix.presale.style import get_fonts
 
@@ -178,7 +180,33 @@ class OrganizerDisplaySettingsForm(SettingsForm):
         required=False,
         validators=[
             RegexValidator(regex='^#[0-9a-fA-F]{6}$',
-                           message=_('Please enter the hexadecimal code of a color, e.g. #990000.'))
+                           message=_('Please enter the hexadecimal code of a color, e.g. #990000.')),
+            ColorContrastValidator()
+        ],
+        widget=forms.TextInput(attrs={'class': 'colorpickerfield'})
+    )
+    theme_color_success = forms.CharField(
+        label=_("Accent color for success"),
+        help_text=_("We strongly suggest to use a dark shade of green that has a good contrast for text on white "
+                    "ground."),
+        required=False,
+        validators=[
+            RegexValidator(regex='^#[0-9a-fA-F]{6}$',
+                           message=_('Please enter the hexadecimal code of a color, e.g. #990000.')),
+            ColorContrastValidator()
+        ],
+        widget=forms.TextInput(attrs={'class': 'colorpickerfield'})
+    )
+    theme_color_danger = forms.CharField(
+        label=_("Accent color for errors"),
+        help_text=_("We strongly suggest to use a dark shade of red that has a good contrast for text on white "
+                    "ground."),
+        required=False,
+        validators=[
+            RegexValidator(regex='^#[0-9a-fA-F]{6}$',
+                           message=_('Please enter the hexadecimal code of a color, e.g. #990000.')),
+
+            ColorContrastValidator()
         ],
         widget=forms.TextInput(attrs={'class': 'colorpickerfield'})
     )