Add dark mode option

src/App.tsx

@@ -17,6 +17,7 @@ import DaySchedule from './components/day-schedule';
 import SimulationChart from './components/simulation-chart';
 import Settings from './components/settings';
 import LanguageSelector from './components/language-selector';
+import ThemeSelector from './components/theme-selector';
 import DisclaimerModal from './components/disclaimer-modal';
 import DataManagementModal from './components/data-management-modal';
 import { Button } from './components/ui/button';
@@ -91,6 +92,33 @@ const MedPlanAssistant = () => {
     uiSettings
   } = appState;
 
+  // Apply theme based on user preference or system setting
+  React.useEffect(() => {
+    const theme = uiSettings.theme || 'system';
+    const root = document.documentElement;
+
+    const applyTheme = (isDark: boolean) => {
+      if (isDark) {
+        root.classList.add('dark');
+      } else {
+        root.classList.remove('dark');
+      }
+    };
+
+    if (theme === 'system') {
+      // Detect system preference
+      const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)');
+      applyTheme(mediaQuery.matches);
+
+      // Listen for system theme changes
+      const listener = (e: MediaQueryListEvent) => applyTheme(e.matches);
+      mediaQuery.addEventListener('change', listener);
+      return () => mediaQuery.removeEventListener('change', listener);
+    } else {
+      applyTheme(theme === 'dark');
+    }
+  }, [uiSettings.theme]);
+
   const {
     showDayTimeOnXAxis,
     chartView,
@@ -137,11 +165,18 @@ const MedPlanAssistant = () => {
 
         <div className="max-w-7xl mx-auto">
           <header className="mb-8">
-            <div className="flex justify-between items-start">
+            <div className="flex justify-between items-start gap-4">
             <div>
               <h1 className="text-3xl md:text-4xl font-bold tracking-tight">{t('appTitle')}</h1>
             </div>
-            <LanguageSelector currentLanguage={currentLanguage} onLanguageChange={changeLanguage} t={t} />
+            <div className="flex flex-wrap gap-2 justify-end">
+              <ThemeSelector
+                currentTheme={uiSettings.theme || 'system'}
+                onThemeChange={(theme: 'light' | 'dark' | 'system') => updateUiSetting('theme', theme)}
+                t={t}
+              />
+              <LanguageSelector currentLanguage={currentLanguage} onLanguageChange={changeLanguage} t={t} />
+            </div>
           </div>
           <p className="text-muted-foreground mt-1">{t('appSubtitle')}</p>
         </header>

src/components/data-management-modal.tsx

@@ -112,6 +112,7 @@ const DataManagementModal: React.FC<DataManagementModalProps> = ({
   const [jsonValidationMessage, setJsonValidationMessage] = useState<{
     type: 'success' | 'error' | null;
     message: string;
+    warnings?: string[];
   }>({ type: null, message: '' });
 
   // Clipboard feedback
@@ -119,30 +120,31 @@ const DataManagementModal: React.FC<DataManagementModalProps> = ({
 
   // Reset editor when modal opens/closes
   React.useEffect(() => {
-    if (isOpen) {
-      // Load current app data into editor when opening
-      const appState = {
-        pkParams,
-        days,
-        therapeuticRange,
-        doseIncrement,
-        uiSettings,
-        steadyStateConfig: { daysOnMedication: pkParams.advanced.steadyStateDays },
-      };
-      const exportData = exportSettings(appState, exportOptions, APP_VERSION);
-      const jsonString = JSON.stringify(exportData, null, 2);
-      setJsonEditorContent(jsonString);
-      setJsonEditorExpanded(true);
-      validateJsonContent(jsonString);
-    } else {
-      // Clear editor when closing
-      setJsonEditorContent('');
-      setJsonEditorExpanded(false);
-      setJsonValidationMessage({ type: null, message: '' });
-      setSelectedFile(null);
-      if (fileInputRef.current) {
+    // TODO nice to have: use can decide behavior via checkbox (near editor)
+    // if (isOpen) {
+    //   // Load current app data into editor when opening
+    //   const appState = {
+    //     pkParams,
+    //     days,
+    //     therapeuticRange,
+    //     doseIncrement,
+    //     uiSettings,
+    //     steadyStateConfig: { daysOnMedication: pkParams.advanced.steadyStateDays },
+    //   };
+    //   const exportData = exportSettings(appState, exportOptions, APP_VERSION);
+    //   const jsonString = JSON.stringify(exportData, null, 2);
+    //   setJsonEditorContent(jsonString);
+    //   setJsonEditorExpanded(true);
+    //   validateJsonContent(jsonString);
+    // } else {
+
+    // Clear/collapse editor and clear upload file ref when opening/closing
+    setJsonEditorContent('');
+    setJsonEditorExpanded(false);
+    setJsonValidationMessage({ type: null, message: '' });
+    setSelectedFile(null);
+    if (fileInputRef.current) {
         fileInputRef.current.value = '';
-      }
     }
   }, [isOpen]);
 
@@ -300,9 +302,11 @@ const DataManagementModal: React.FC<DataManagementModalProps> = ({
       }
 
       if (validation.warnings.length > 0) {
+        // Show success with warnings - warnings will be displayed separately
         setJsonValidationMessage({
           type: 'success',
-          message: t('jsonValidationSuccess') + ' ⚠️ ' + validation.warnings.length + ' warnings',
+          message: t('jsonValidationSuccess'),
+          warnings: validation.warnings,
         });
         return;
       }
@@ -734,19 +738,33 @@ const DataManagementModal: React.FC<DataManagementModalProps> = ({
                     />
 
                     {jsonValidationMessage.type && (
-                      <div
-                        className={`flex items-center gap-2 text-sm ${
-                          jsonValidationMessage.type === 'success'
-                            ? 'text-green-600 dark:text-green-400'
-                            : 'text-red-600 dark:text-red-400'
-                        }`}
-                      >
-                        {jsonValidationMessage.type === 'success' ? (
-                          <Check className="h-4 w-4" />
-                        ) : (
-                          <X className="h-4 w-4" />
+                      <div className="space-y-2">
+                        <div
+                          className={`flex items-center gap-2 text-sm ${
+                            jsonValidationMessage.type === 'success'
+                              ? 'text-green-600 dark:text-green-400'
+                              : 'text-red-600 dark:text-red-400'
+                          }`}
+                        >
+                          {jsonValidationMessage.type === 'success' ? (
+                            <Check className="h-4 w-4 flex-shrink-0" />
+                          ) : (
+                            <X className="h-4 w-4 flex-shrink-0" />
+                          )}
+                          <span>{jsonValidationMessage.message}</span>
+                        </div>
+                        {jsonValidationMessage.warnings && jsonValidationMessage.warnings.length > 0 && (
+                          <div className="space-y-1.5">
+                            {jsonValidationMessage.warnings.map((warning, index) => (
+                              <div
+                                key={index}
+                                className="bg-yellow-500 text-white text-xs p-2 rounded-md"
+                              >
+                                {warning}
+                              </div>
+                            ))}
+                          </div>
                         )}
-                        <span>{jsonValidationMessage.message}</span>
                       </div>
                     )}
 

src/components/language-selector.tsx

@@ -10,22 +10,18 @@
 
 import React from 'react';
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from './ui/select';
-import { Label } from './ui/label';
 
 const LanguageSelector = ({ currentLanguage, onLanguageChange, t }: any) => {
   return (
-    <div className="flex flex-wrap-reverse items-center gap-2">
-      <Label className="text-sm font-medium">{t('languageSelectorLabel')}</Label>
-      <Select value={currentLanguage} onValueChange={onLanguageChange}>
-        <SelectTrigger className="w-32">
-          <SelectValue />
-        </SelectTrigger>
-        <SelectContent>
-          <SelectItem value="en">{t('languageSelectorEN')}</SelectItem>
-          <SelectItem value="de">{t('languageSelectorDE')}</SelectItem>
-        </SelectContent>
-      </Select>
-    </div>
+    <Select value={currentLanguage} onValueChange={onLanguageChange}>
+      <SelectTrigger className="w-32">
+        <SelectValue />
+      </SelectTrigger>
+      <SelectContent>
+        <SelectItem value="en">{t('languageSelectorEN')}</SelectItem>
+        <SelectItem value="de">{t('languageSelectorDE')}</SelectItem>
+      </SelectContent>
+    </Select>
   );
 };
 

src/components/theme-selector.tsx

@@ -0,0 +1,29 @@
+/**
+ * Theme Selector Component
+ *
+ * Provides UI for switching between light/dark/system theme modes.
+ * Uses shadcn/ui Select component.
+ *
+ * @author Andreas Weyer
+ * @license MIT
+ */
+
+import React from 'react';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from './ui/select';
+
+const ThemeSelector = ({ currentTheme, onThemeChange, t }: any) => {
+  return (
+    <Select value={currentTheme} onValueChange={onThemeChange}>
+      <SelectTrigger className="w-36">
+        <SelectValue />
+      </SelectTrigger>
+      <SelectContent>
+        <SelectItem value="light">{t('themeSelectorLight')}</SelectItem>
+        <SelectItem value="dark">{t('themeSelectorDark')}</SelectItem>
+        <SelectItem value="system">{t('themeSelectorSystem')}</SelectItem>
+      </SelectContent>
+    </Select>
+  );
+};
+
+export default ThemeSelector;

src/constants/defaults.ts

@@ -99,6 +99,7 @@ export interface UiSettings {
   showTherapeuticRange?: boolean;
   steadyStateDaysEnabled?: boolean;
   stickyChart: boolean;
+  theme?: 'light' | 'dark' | 'system';
 }
 
 export interface AppState {
@@ -171,5 +172,6 @@ export const getDefaultState = (): AppState => ({
     showTherapeuticRange: false,
     steadyStateDaysEnabled: true,
     stickyChart: false,
+    theme: 'system',
   }
 });

src/locales/de.ts

@@ -17,6 +17,11 @@ export const de = {
   languageSelectorEN: "English",
   languageSelectorDE: "Deutsch",
 
+  // Theme selector
+  themeSelectorLight: "☀️ Hell",
+  themeSelectorDark: "🌙 Dunkel",
+  themeSelectorSystem: "💻 System",
+
   // Dose Schedule
   myPlan: "Mein Plan",
   morning: "Morgens",

src/locales/en.ts

@@ -17,6 +17,11 @@ export const en = {
   languageSelectorEN: "English",
   languageSelectorDE: "Deutsch",
 
+  // Theme selector
+  themeSelectorLight: "☀️ Light",
+  themeSelectorDark: "🌙 Dark",
+  themeSelectorSystem: "💻 System",
+
   // Dose Schedule
   myPlan: "My Plan",
   morning: "Morning",

src/styles/global.css

@@ -31,6 +31,33 @@
     --radius: 0.625rem;
   }
 
+  .dark {
+    --background: 0 0% 10%;
+    --foreground: 0 0% 95%;
+    --card: 0 0% 14%;
+    --card-foreground: 0 0% 95%;
+    --popover: 0 0% 12%;
+    --popover-foreground: 0 0% 95%;
+    --primary: 217 91% 60%;
+    --primary-foreground: 0 0% 100%;
+    --secondary: 220 15% 20%;
+    --secondary-foreground: 0 0% 90%;
+    --muted: 220 10% 18%;
+    --muted-foreground: 0 0% 60%;
+    --accent: 220 10% 18%;
+    --accent-foreground: 0 0% 90%;
+    --destructive: 0 84% 60%;
+    --destructive-foreground: 0 0% 98%;
+    --border: 0 0% 25%;
+    --input: 0 0% 25%;
+    --ring: 0 0% 40%;
+    --chart-1: 12 76% 61%;
+    --chart-2: 173 58% 39%;
+    --chart-3: 197 37% 24%;
+    --chart-4: 43 74% 66%;
+    --chart-5: 27 87% 67%;
+  }
+
   * {
     border-color: hsl(var(--border));
   }

src/utils/exportImport.ts

@@ -219,7 +219,7 @@ export const validateImportData = (data: any): ImportValidationResult => {
 
   // Validate advanced settings
   if (importData.advancedSettings !== undefined) {
-    const validCategories = ['standardVd', 'weightBasedVd', 'foodEffect', 'urinePh', 'fOral', 'steadyStateDays'];
+    const validCategories = ['standardVd', 'weightBasedVd', 'foodEffect', 'urinePh', 'fOral', 'steadyStateDays', 'ageGroup', 'renalFunction'];
     const importedCategories = Object.keys(importData.advancedSettings);
     const unknownCategories = importedCategories.filter(c => !validCategories.includes(c));
     if (unknownCategories.length > 0) {