themes verbessert, inkl about page

Project_Periodensystem.Controller/PeriodensystemController.cs

@@ -1,17 +1,196 @@
-using System.Collections.ObjectModel;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using Project_Periodensystem.Model;
 using Project_Periodensystem.Persistence;
 
 namespace Project_Periodensystem.Controller
 {
+    /// <summary>
+    /// Controller für das Periodensystem - verwaltet die Geschäftslogik
+    /// und trennt View von Model gemäß MVC-Pattern
+    /// </summary>
     public class PeriodensystemController
     {
-        public ObservableCollection<Element> Elements { get; }
+        // Nullable Field um Warning zu vermeiden
+        private List<Element> _elements = new List<Element>();
 
+        /// <summary>
+        /// Konstruktor - initialisiert den Controller
+        /// </summary>
         public PeriodensystemController()
         {
-            // Gießt die statische List<> in eine ObservableCollection
+            LoadElements();
-            Elements = new ObservableCollection<Element>(PeriodicTableData.Elements);
+        }
+
+        /// <summary>
+        /// Lädt alle Elemente über den Persistence-Layer
+        /// </summary>
+        private void LoadElements()
+        {
+            try
+            {
+                // Verwende die korrekte statische Methode aus PeriodicTableData
+                _elements = PeriodicTableData.Elements.ToList();
+                Logger.Log($"Controller: {_elements.Count} Elemente erfolgreich geladen");
+            }
+            catch (Exception ex)
+            {
+                Logger.Log($"EXCEPTION in LoadElements: {ex.Message}");
+                _elements = new List<Element>();
+            }
+        }
+
+        /// <summary>
+        /// Gibt alle verfügbaren Elemente zurück
+        /// </summary>
+        /// <returns>Liste aller Elemente</returns>
+        public List<Element> GetAllElements()
+        {
+            return _elements;
+        }
+
+        /// <summary>
+        /// Sucht ein Element nach Atomnummer
+        /// </summary>
+        /// <param name="atomicNumber">Atomnummer des gesuchten Elements</param>
+        /// <returns>Element oder null wenn nicht gefunden</returns>
+        public Element? GetElementByAtomicNumber(int atomicNumber)
+        {
+            if (atomicNumber <= 0)
+            {
+                Logger.Log($"Ungültige Atomnummer: {atomicNumber}");
+                return null;
+            }
+
+            return _elements.FirstOrDefault(e => e.AtomicNumber == atomicNumber);
+        }
+
+        /// <summary>
+        /// Sucht ein Element nach Symbol
+        /// </summary>
+        /// <param name="symbol">Symbol des gesuchten Elements</param>
+        /// <returns>Element oder null wenn nicht gefunden</returns>
+        public Element? GetElementBySymbol(string symbol)
+        {
+            if (string.IsNullOrWhiteSpace(symbol))
+            {
+                Logger.Log("Leeres Symbol übergeben");
+                return null;
+            }
+
+            return _elements.FirstOrDefault(e => 
+                string.Equals(e.Symbol, symbol, StringComparison.OrdinalIgnoreCase));
+        }
+
+        /// <summary>
+        /// Filtert Elemente nach Serie
+        /// </summary>
+        /// <param name="series">Gewünschte Elementserie</param>
+        /// <returns>Liste der Elemente der angegebenen Serie</returns>
+        public List<Element> GetElementsBySeries(string series)
+        {
+            if (string.IsNullOrWhiteSpace(series))
+            {
+                return new List<Element>();
+            }
+
+            return _elements.Where(e => 
+                string.Equals(e.Series, series, StringComparison.OrdinalIgnoreCase))
+                .ToList();
+        }
+
+        /// <summary>
+        /// Validiert Grid-Position eines Elements
+        /// </summary>
+        /// <param name="element">Zu validierendes Element</param>
+        /// <returns>True wenn Position gültig ist</returns>
+        public bool ValidateElementPosition(Element element)
+        {
+            if (element == null)
+            {
+                Logger.Log("Null-Element kann nicht validiert werden");
+                return false;
+            }
+
+            // Periodensystem hat 7 Perioden (0-6) und 18 Gruppen (0-17)
+            // Plus Lanthanoid/Actinoid-Reihen bei Zeile 8 und 9
+            bool validRow = element.Row >= 0 && element.Row <= 9;
+            bool validColumn = element.Column >= 0 && element.Column <= 17;
+
+            if (!validRow || !validColumn)
+            {
+                Logger.Log($"Ungültige Position für {element.Symbol}: ({element.Row},{element.Column})");
+                return false;
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// Gibt alle verfügbaren Element-Serien zurück
+        /// </summary>
+        /// <returns>Liste aller Serien</returns>
+        public List<string> GetAllSeries()
+        {
+            return _elements.Select(e => e.Series)
+                           .Distinct()
+                           .Where(s => !string.IsNullOrWhiteSpace(s))
+                           .OrderBy(s => s)
+                           .ToList();
+        }
+
+        /// <summary>
+        /// Überprüft ob alle Elemente korrekt geladen wurden
+        /// </summary>
+        /// <returns>True wenn Daten vollständig sind</returns>
+        public bool ValidateData()
+        {
+            if (_elements.Count == 0)
+            {
+                Logger.Log("Keine Elemente geladen");
+                return false;
+            }
+
+            // Überprüfe auf Duplikate bei Atomnummern
+            var duplicateNumbers = _elements.GroupBy(e => e.AtomicNumber)
+                                           .Where(g => g.Count() > 1)
+                                           .Select(g => g.Key);
+
+            if (duplicateNumbers.Any())
+            {
+                Logger.Log($"Doppelte Atomnummern gefunden: {string.Join(", ", duplicateNumbers)}");
+                return false;
+            }
+
+            // Überprüfe auf leere Symbole
+            var emptySymbols = _elements.Where(e => string.IsNullOrWhiteSpace(e.Symbol));
+            if (emptySymbols.Any())
+            {
+                Logger.Log("Elemente mit leeren Symbolen gefunden");
+                return false;
+            }
+
+            Logger.Log($"Datenvalidierung erfolgreich - {_elements.Count} Elemente validiert");
+            return true;
+        }
+
+        /// <summary>
+        /// Lädt Daten neu (für Refresh-Funktionalität)
+        /// </summary>
+        public void RefreshData()
+        {
+            Logger.Log("Daten werden neu geladen...");
+            LoadElements();
+        }
+
+        /// <summary>
+        /// Gibt die Anzahl der geladenen Elemente zurück
+        /// </summary>
+        /// <returns>Anzahl der Elemente</returns>
+        public int GetElementCount()
+        {
+            return _elements.Count;
         }
     }
 }

Project_Periodensystem.Model/Logger.cs

@@ -0,0 +1,136 @@
+using System;
+using System.IO;
+
+namespace Project_Periodensystem.Model
+{
+    /// <summary>
+    /// Einfacher Logger für Debug-Ausgaben und Fehlerprotokollierung
+    /// </summary>  
+    public static class Logger
+    {
+        private static readonly string LogFilePath = Path.Combine(
+            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+            "Periodensystem", "app.log");
+
+        /// <summary>
+        /// Statischer Initializer - erstellt Log-Verzeichnis
+        /// </summary>
+        static Logger()
+        {
+            try
+            {
+                var logDirectory = Path.GetDirectoryName(LogFilePath);
+                if (logDirectory != null && !Directory.Exists(logDirectory))
+                {
+                    Directory.CreateDirectory(logDirectory);
+                }
+            }
+            catch
+            {
+                // Falls Log-Datei nicht erstellt werden kann, nur Konsole verwenden
+            }
+        }
+
+        /// <summary>
+        /// Protokolliert eine Nachricht sowohl in Konsole als auch Datei
+        /// </summary>
+        /// <param name="message">Zu protokollierende Nachricht</param>
+        public static void Log(string message)
+        {
+            if (string.IsNullOrWhiteSpace(message))
+                return;
+
+            var timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
+            var logEntry = $"[{timestamp}] {message}";
+
+            // Konsolen-Ausgabe (für Debug)
+            Console.WriteLine(logEntry);
+
+            // Datei-Ausgabe (für Persistenz)
+            try
+            {
+                File.AppendAllText(LogFilePath, logEntry + Environment.NewLine);
+            }
+            catch
+            {
+                // Fehler beim Schreiben ignorieren um App nicht zum Absturz zu bringen
+            }
+        }
+
+        /// <summary>
+        /// Protokolliert eine Exception mit Stack-Trace
+        /// </summary>
+        /// <param name="ex">Exception die protokolliert werden soll</param>
+        /// <param name="context">Zusätzlicher Kontext</param>
+        public static void LogException(Exception ex, string context = "")
+        {
+            if (ex == null)
+            {
+                Log("Null-Exception übergeben");
+                return;
+            }
+
+            var message = string.IsNullOrWhiteSpace(context) 
+                ? $"EXCEPTION: {ex.Message}\nStack: {ex.StackTrace}"
+                : $"EXCEPTION in {context}: {ex.Message}\nStack: {ex.StackTrace}";
+            
+            Log(message);
+        }
+
+        /// <summary>
+        /// Protokolliert eine Warnung
+        /// </summary>
+        /// <param name="message">Warnung</param>
+        public static void LogWarning(string message)
+        {
+            Log($"WARNING: {message}");
+        }
+
+        /// <summary>
+        /// Protokolliert einen Fehler
+        /// </summary>
+        /// <param name="message">Fehlermeldung</param>
+        public static void LogError(string message)
+        {
+            Log($"ERROR: {message}");
+        }
+
+        /// <summary>
+        /// Protokolliert Debug-Informationen (nur in Debug-Build)
+        /// </summary>
+        /// <param name="message">Debug-Nachricht</param>
+        [System.Diagnostics.Conditional("DEBUG")]
+        public static void LogDebug(string message)
+        {
+            Log($"DEBUG: {message}"); 
+        }
+
+        /// <summary>
+        /// Löscht die Log-Datei (für Cleanup)
+        /// </summary>
+        public static void ClearLog()
+        {
+            try
+            {
+                if (File.Exists(LogFilePath))
+                {
+                    File.Delete(LogFilePath);
+                    Log("Log-Datei gelöscht");
+                }
+            }
+            catch (Exception ex)
+            {
+                Log($"Fehler beim Löschen der Log-Datei: {ex.Message}");
+            }
+        }
+
+        /// <summary>
+        /// Gibt den Pfad zur Log-Datei zurück
+        /// </summary>
+        /// <returns>Vollständiger Pfad zur Log-Datei</returns>
+        public static string GetLogFilePath()
+        {
+            return LogFilePath;
+        }
+    }
+}

Project_Periodensystem.Model/Theme.cs

@@ -1,9 +0,0 @@
-namespace Project_Periodensystem.Model
-{
-    public enum AppTheme
-    {
-        Dark,
-        Light,
-        Classic
-    }
-}

Project_Periodensystem.View/AboutPage.axaml

@@ -1,7 +1,6 @@
 <!-- Datei: Project_Periodensystem.View/AboutPage.axaml -->
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:i="using:Avalonia.Interactivity"
              x:Class="Project_Periodensystem.View.AboutPage">
 
     <UserControl.Styles>
@@ -10,10 +9,11 @@
             <Setter Property="Foreground" Value="White"/>
             <Setter Property="FontFamily" Value="Arial"/>
             <Setter Property="FontWeight" Value="Bold"/>
-            <Setter Property="Width" Value="250"/>
+            <Setter Property="Width" Value="200"/>
             <Setter Property="Height" Value="40"/>
             <Setter Property="HorizontalContentAlignment" Value="Center"/>
             <Setter Property="VerticalContentAlignment" Value="Center"/>
+            <Setter Property="CornerRadius" Value="5"/>
         </Style>
         <Style Selector="Button:pointerover /template/ ContentPresenter">
             <Setter Property="Background" Value="DarkRed"/>
@@ -22,49 +22,142 @@
             <Setter Property="Background" Value="Red"/>
         </Style>
         <Style Selector="Button TextBlock">
-            <Setter Property="FontSize" Value="16"/>
+            <Setter Property="FontSize" Value="14"/>
             <Setter Property="FontFamily" Value="Arial"/>
             <Setter Property="FontWeight" Value="Bold"/>
+            <Setter Property="Foreground" Value="White"/>
+        </Style>
+        
+        <!-- Spezielle Styles für About-Seite -->
+        <Style Selector="TextBlock.Title">
+            <Setter Property="FontSize" Value="36"/>
+            <Setter Property="FontWeight" Value="Bold"/>
+            <Setter Property="HorizontalAlignment" Value="Center"/>
+            <Setter Property="Margin" Value="0,0,0,30"/>
+        </Style>
+        
+        <Style Selector="TextBlock.Subtitle">
+            <Setter Property="FontSize" Value="18"/>
+            <Setter Property="FontWeight" Value="Normal"/>
+            <Setter Property="HorizontalAlignment" Value="Center"/>
+            <Setter Property="Margin" Value="0,10"/>
+        </Style>
+        
+        <Style Selector="TextBlock.InfoBold">
+            <Setter Property="FontSize" Value="16"/>
+            <Setter Property="FontWeight" Value="Bold"/>
+            <Setter Property="HorizontalAlignment" Value="Center"/>
+            <Setter Property="Margin" Value="0,5"/>
+        </Style>
+        
+        <Style Selector="TextBlock.Info">
+            <Setter Property="FontSize" Value="14"/>
+            <Setter Property="FontWeight" Value="Normal"/>
+            <Setter Property="HorizontalAlignment" Value="Center"/>
+            <Setter Property="Margin" Value="0,3"/>
+        </Style>
+        
+        <!-- Einfache Theme-unabhängige Styles -->
+        <Style Selector="Border.InfoCard">
+            <Setter Property="CornerRadius" Value="10"/>
+            <Setter Property="Padding" Value="30,25"/>
+            <Setter Property="Margin" Value="20"/>
+            <Setter Property="BorderThickness" Value="1"/>
+            <Setter Property="BoxShadow" Value="0 4 8 0 #40000000"/>
+        </Style>
+        
+        <!-- Theme-Ressourcen verwenden -->
+        <Style Selector="Border.InfoCard">
+            <Setter Property="Background" Value="{DynamicResource SystemControlBackgroundChromeMediumBrush}"/>
+            <Setter Property="BorderBrush" Value="{DynamicResource SystemControlForegroundBaseMediumLowBrush}"/>
+        </Style>
+        
+        <Style Selector="Rectangle.Divider">
+            <Setter Property="Fill" Value="{DynamicResource SystemControlForegroundBaseMediumLowBrush}"/>
         </Style>
     </UserControl.Styles>
 
-    <Grid>
+    <Grid Margin="20">
         <Grid.RowDefinitions>
             <RowDefinition Height="*"/>
             <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="*"/>
         </Grid.RowDefinitions>
 
-        <!-- Content -->
+        <!-- Titel -->
-        <StackPanel Grid.Row="0" 
+        <TextBlock Grid.Row="1" 
-                    VerticalAlignment="Center" 
+                   Classes="Title"
-                    HorizontalAlignment="Center">
+                   Text="Periodensystem der Elemente"/>
-            <TextBlock Text="Author: Oliver Träger"
-                      FontSize="24"
-                      Margin="0,0,0,20"/>
-            <TextBlock Text="Klasse: ITFS2"
-                      FontSize="24"
-                      Margin="0,0,0,20"/>
-        </StackPanel>
 
-        <!-- Footer with Buttons -->
+        <!-- Info-Card -->
-        <Grid Grid.Row="1" 
+        <Border Grid.Row="2" 
-              HorizontalAlignment="Stretch"
+                Classes="InfoCard"
-              Margin="20,0,20,20">
+                MaxWidth="600">
+            <StackPanel>
+                <!-- Projekt Info -->
+                <TextBlock Classes="Subtitle" 
+                           Text="Projekt Information"/>
+                
+                <Rectangle Classes="Divider"
+                           Height="2" 
+                           Margin="0,10,0,20"/>
+                
+                <TextBlock Classes="InfoBold" 
+                           Text="Author:"/>
+                <TextBlock Classes="Info" 
+                           Text="Oliver Träger"/>
+                
+                <TextBlock Classes="InfoBold" 
+                           Text="Klasse:" 
+                           Margin="0,15,0,0"/>
+                <TextBlock Classes="Info" 
+                           FontWeight="Bold"
+                           Text="ITFS2"/>
+                
+                <TextBlock Classes="InfoBold" 
+                           Text="Semester:" 
+                           Margin="0,15,0,0"/>
+                <TextBlock Classes="Info" 
+                           FontWeight="Bold"
+                           Text="Sommersemester 2025"/>
+                
+                <Rectangle Classes="Divider"
+                           Height="2" 
+                           Margin="0,25,0,15"/>
+                
+                <!-- Technische Details -->
+                <TextBlock Classes="Info" 
+                           Text="Entwickelt mit Avalonia UI Framework"/>
+                <TextBlock Classes="Info" 
+                           Text="MVC-Architektur mit C# .NET"/>
+                <TextBlock Classes="Info" 
+                           Text="Interaktives Periodensystem mit 118 Elementen"/>
+            </StackPanel>
+        </Border>
+
+        <!-- Button-Bereich -->
+        <Grid Grid.Row="3" 
+              Margin="0,30,0,0">
             <Grid.ColumnDefinitions>
                 <ColumnDefinition Width="*"/>
+                <ColumnDefinition Width="Auto"/>
+                <ColumnDefinition Width="20"/>
+                <ColumnDefinition Width="Auto"/>
                 <ColumnDefinition Width="*"/>
             </Grid.ColumnDefinitions>
 
-            <Button Grid.Column="0"
+            <Button Name="BackButton"
-                    HorizontalAlignment="Left"
+                    Grid.Column="1"
-                    Click="ThemeButton_Click">
+                    Click="BackButton_Click">
-                <TextBlock Text="Theme wechseln"/>
+                <TextBlock Text="← Zurück"/>
             </Button>
 
-            <Button Grid.Column="1"
+            <Button Name="ThemeButton"
-                    HorizontalAlignment="Right"
+                    Grid.Column="3"
-                    Click="BackButton_Click">
+                    Click="ThemeButton_Click">
-                <TextBlock Text="Zurück"/>
+                <TextBlock Text="Theme wechseln"/>
             </Button>
         </Grid>
     </Grid>

Project_Periodensystem.View/AboutPage.axaml.cs

@@ -8,44 +8,67 @@ using Project_Periodensystem.Model;
 
 namespace Project_Periodensystem.View
 {
+    /// <summary>
+    /// Code-Behind für die About-Seite
+    /// </summary>
     public partial class AboutPage : UserControl
     {
+        /// <summary>
+        /// Konstruktor
+        /// </summary>
         public AboutPage()
         {
             InitializeComponent();
         }
 
-        protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
-        {
-            base.OnAttachedToVisualTree(e);
-            
-            if (this.GetVisualRoot() is MainWindow mainWindow)
-            {
-                mainWindow.UpdateTheme(MainWindow.CurrentTheme);
-            }
-        }
-
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);
         }
 
+        /// <summary>
+        /// Zurück-Button - Navigation zur Landing Page
+        /// </summary>
         private void BackButton_Click(object? sender, RoutedEventArgs e)
         {
-            if (MainWindow.Instance != null)
+            try
             {
-                MainWindow.Instance.ShowLandingPage();
+                var mainWindow = TopLevel.GetTopLevel(this) as Window;
+                if (mainWindow != null)
+                {
+                    var landingPage = new LandingPage();
+                    mainWindow.Content = landingPage;
+                    Logger.Log("Navigation zurück zur Landing Page");
+                }
+            }
+            catch (System.Exception ex)
+            {
+                Logger.Log($"Fehler bei Navigation zurück: {ex.Message}");
             }
         }
 
+        /// <summary>
+        /// Event-Handler für Theme-Button - VEREINHEITLICHT mit anderen Seiten
+        /// </summary>
         private void ThemeButton_Click(object? sender, RoutedEventArgs e)
         {
-            var themes = Enum.GetValues<AppTheme>();
+            try
-            MainWindow.CurrentTheme = themes[(Array.IndexOf(themes, MainWindow.CurrentTheme) + 1) % themes.Length];
-            
-            if (MainWindow.Instance != null)
             {
-                MainWindow.Instance.UpdateTheme(MainWindow.CurrentTheme);
+                // GLEICHE LOGIK wie auf LandingPage und PeriodicTablePage
+                var app = Application.Current;
+                if (app != null)
+                {
+                    var currentTheme = app.ActualThemeVariant;
+                    app.RequestedThemeVariant = currentTheme == Avalonia.Styling.ThemeVariant.Dark 
+                        ? Avalonia.Styling.ThemeVariant.Light 
+                        : Avalonia.Styling.ThemeVariant.Dark;
+                    
+                    Logger.Log($"Theme gewechselt zu: {app.RequestedThemeVariant}");
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.Log($"Fehler beim Theme-Wechsel: {ex.Message}");
             }
         }
     }

Project_Periodensystem.View/App.axaml

@@ -1,7 +1,9 @@
 <Application xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             x:Class="Project_Periodensystem.View.App">
+             x:Class="Project_Periodensystem.View.App"
-  <Application.Styles>
+             RequestedThemeVariant="Dark">
-    <FluentTheme />
+    
-  </Application.Styles>
+    <Application.Styles>
+        <FluentTheme />
+    </Application.Styles>
 </Application>

Project_Periodensystem.View/App.axaml.cs

@@ -1,6 +1,7 @@
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
+using Project_Periodensystem.Model;
 
 namespace Project_Periodensystem.View
 {
@@ -15,7 +16,11 @@ namespace Project_Periodensystem.View
         {
             if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
             {
+                // Standard Dark Theme beim Start
+                RequestedThemeVariant = Avalonia.Styling.ThemeVariant.Dark;
+                
                 desktop.MainWindow = new MainWindow();
+                Logger.Log("Application initialized with Dark theme");
             }
 
             base.OnFrameworkInitializationCompleted();

Project_Periodensystem.View/LandingPage.axaml

@@ -8,6 +8,8 @@
             <Setter Property="Foreground" Value="White"/>
             <Setter Property="FontFamily" Value="Arial"/>
             <Setter Property="FontWeight" Value="Bold"/>
+            <Setter Property="Width" Value="250"/>
+            <Setter Property="Height" Value="40"/>
             <Setter Property="HorizontalContentAlignment" Value="Center"/>
             <Setter Property="VerticalContentAlignment" Value="Center"/>
         </Style>
@@ -17,50 +19,53 @@
         <Style Selector="Button:pressed /template/ ContentPresenter">
             <Setter Property="Background" Value="Red"/>
         </Style>
+        <Style Selector="Button TextBlock">
+            <Setter Property="FontSize" Value="16"/>
+            <Setter Property="FontFamily" Value="Arial"/>
+            <Setter Property="FontWeight" Value="Bold"/>
+            <Setter Property="Foreground" Value="White"/>
+        </Style>
     </UserControl.Styles>
 
     <Grid>
         <Grid.RowDefinitions>
             <RowDefinition Height="*"/>
             <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="*"/>
         </Grid.RowDefinitions>
 
-        <!-- Hauptcontent -->
+        <TextBlock Grid.Row="1" 
-        <Grid Grid.Row="0">
+                   Text="Periodensystem der Elemente" 
-            <StackPanel VerticalAlignment="Center" 
+                   FontSize="32" 
-                       Margin="0,-100,0,0">
+                   FontWeight="Bold" 
-                <TextBlock Text="Willkommen zum"
+                   HorizontalAlignment="Center" 
-                         FontSize="36"
+                   Margin="0,0,0,50"/>
-                         FontWeight="Light"
-                         HorizontalAlignment="Center"
-                         Margin="0,0,0,10"/>
 
-                <TextBlock Text="Periodensystem der Elemente!"
+        <Button Grid.Row="2" 
-                         FontSize="72"
+                Name="PeriodicTableButton"
-                         FontWeight="Bold"
+                Click="PeriodicTableButton_Click"
-                         HorizontalAlignment="Center"
+                HorizontalAlignment="Center" 
-                         Margin="0,0,0,40"/>
+                Margin="0,10">
+            <TextBlock Text="Periodensystem anzeigen"/>
+        </Button>
 
-                <Button Name="StartButton"
+        <Button Grid.Row="3" 
-                        Width="200"
+                Name="ThemeButton"
-                        Height="60"
-                        HorizontalAlignment="Center"
-                        Click="StartButton_Click">
-                    <TextBlock Text="Start" FontSize="24"/>
-                </Button>
-            </StackPanel>
-        </Grid>
-
-        <!-- Theme Button -->
-        <Button Name="ThemeButton"
-                Grid.Row="1"
                 Click="ThemeButton_Click"
-                HorizontalAlignment="Left"
+                HorizontalAlignment="Center" 
-                VerticalAlignment="Bottom"
+                Margin="0,10">
-                Width="250"
+            <TextBlock Text="Theme wechseln"/>
-                Height="40"
+        </Button>
-                Margin="20,0,0,20">
+
-            <TextBlock Text="Theme wechseln" FontSize="16"/>
+        <Button Grid.Row="4" 
+                Name="AboutButton"
+                Click="AboutButton_Click"
+                HorizontalAlignment="Center" 
+                Margin="0,10">
+            <TextBlock Text="About"/>
         </Button>
     </Grid>
 </UserControl>

Project_Periodensystem.View/LandingPage.axaml.cs

@@ -1,79 +1,95 @@
 using Avalonia;
 using Avalonia.Controls;
-using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Interactivity;
-using Avalonia.Markup.Xaml;
-using Avalonia.Media;
-using Avalonia.VisualTree;
 using Project_Periodensystem.Model;
-using System;
-using System.Collections.Generic;
 
 namespace Project_Periodensystem.View
 {
+    /// <summary>
+    /// Code-Behind für die Landing Page
+    /// </summary>
     public partial class LandingPage : UserControl
     {
-        private readonly Random random = new();
+        /// <summary>
-        private readonly Dictionary<AppTheme, string> themeColors;
+        /// Konstruktor
-        private DateTime lastClickTime = DateTime.MinValue;
+        /// </summary>
-        private const int DEBOUNCE_MS = 500;
-
         public LandingPage()
         {
-            Logger.Log($"=== LandingPage wird initialisiert am {DateTime.Now:dd.MM.yyyy HH:mm:ss} ===");
             InitializeComponent();
-            
-            themeColors = new Dictionary<AppTheme, string>
-            {
-                { AppTheme.Dark, "#5C5144" },
-                { AppTheme.Light, "#E8DFD8" },
-                { AppTheme.Classic, "#7B8B6F" }
-            };
-            
-            Logger.Log("LandingPage initialisiert");
         }
 
-        private void InitializeComponent()
+        /// <summary>
+        /// Event-Handler für Periodensystem-Button
+        /// </summary>
+        private void PeriodicTableButton_Click(object? sender, RoutedEventArgs e)
         {
-            AvaloniaXamlLoader.Load(this);
+            try
-        }
-
-        private void ThemeButton_Click(object? sender, RoutedEventArgs e)
-        {
-            var themes = Enum.GetValues<AppTheme>();
-            MainWindow.CurrentTheme = themes[(Array.IndexOf(themes, MainWindow.CurrentTheme) + 1) % themes.Length];
-            
-            if (MainWindow.Instance != null)
             {
-                MainWindow.Instance.UpdateTheme(MainWindow.CurrentTheme);
+                var mainWindow = TopLevel.GetTopLevel(this) as Window;
+                if (mainWindow != null)
+                {
+                    var periodicTablePage = new PeriodicTablePage();
+                    mainWindow.Content = periodicTablePage;
+                    Logger.Log("Navigation zum Periodensystem");
+                }
+            }
+            catch (System.Exception ex)
+            {
+                Logger.Log($"Fehler bei Navigation zum Periodensystem: {ex.Message}");
             }
         }
 
-        private void StartButton_Click(object? sender, RoutedEventArgs e)
+        /// <summary>
+        /// Event-Handler für About-Button
+        /// </summary>
+        private void AboutButton_Click(object? sender, RoutedEventArgs e)
         {
-            // Add multiple ways to see if this method is called
-            System.Diagnostics.Debug.WriteLine("StartButton_Click CALLED!");
-            Console.WriteLine("StartButton_Click CALLED!");
-            // Remove the MessageBox line - it's not available
-    
-            Logger.Log("=== StartButton_Click CALLED ===");
-            
             try
             {
-                if (MainWindow.Instance != null)
+                var mainWindow = TopLevel.GetTopLevel(this) as Window;
+                if (mainWindow != null)
                 {
-                    Logger.Log("Found MainWindow instance - calling ShowPeriodicTable");
+                    var aboutPage = new AboutPage();
-                    MainWindow.Instance.ShowPeriodicTable();
+                    mainWindow.Content = aboutPage;
-                    Logger.Log("ShowPeriodicTable called successfully");
+                    Logger.Log("Navigation zur About-Seite");
+                }
+            }
+            catch (System.Exception ex)
+            {
+                Logger.Log($"Fehler bei Navigation zu About: {ex.Message}");
+            }
+        }
+
+        /// <summary>
+        /// Event-Handler für Theme-Button
+        /// </summary>
+        private void ThemeButton_Click(object? sender, RoutedEventArgs e)
+        {
+            try
+            {
+                Logger.Log("Theme-Button geklickt");
+                
+                var app = Application.Current;
+                if (app != null)
+                {
+                    var currentTheme = app.ActualThemeVariant;
+                    Logger.Log($"Aktuelles Theme: {currentTheme}");
+                    
+                    var newTheme = currentTheme == Avalonia.Styling.ThemeVariant.Dark 
+                        ? Avalonia.Styling.ThemeVariant.Light 
+                        : Avalonia.Styling.ThemeVariant.Dark;
+                    
+                    app.RequestedThemeVariant = newTheme;
+                    Logger.Log($"Theme gewechselt zu: {newTheme}");
                 }
                 else
                 {
-                    Logger.Log("MainWindow.Instance is null!");
+                    Logger.Log("Application.Current ist null!");
                 }
             }
-            catch (Exception ex)
+            catch (System.Exception ex)
             {
-                Logger.Log($"ERROR in StartButton_Click: {ex.Message}");
+                Logger.Log($"Fehler beim Theme-Wechsel: {ex.Message}");
             }
         }
     }

Project_Periodensystem.View/MainWindow.axaml.cs

@@ -1,152 +1,65 @@
 using Avalonia;
 using Avalonia.Controls;
-using Avalonia.Media;
-using Avalonia.VisualTree;
-using Avalonia.Threading;
 using Project_Periodensystem.Model;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using static Project_Periodensystem.Model.AppTheme;
 
 namespace Project_Periodensystem.View
 {
+    /// <summary>
+    /// Vereinfachtes MainWindow - nur noch Container für Content
+    /// </summary>
     public partial class MainWindow : Window
     {
         private ContentControl? mainContent;
-        public static AppTheme CurrentTheme { get; set; } = AppTheme.Dark;
-        public static MainWindow? Instance { get; private set; } // Add this line
-        
-        public static Dictionary<AppTheme, (string Background, string Foreground)> ThemeColors { get; } = new()
-        {
-            { AppTheme.Dark, ("#2F2F2F", "#FFFFFF") },
-            { AppTheme.Light, ("#FFFFFF", "#000000") },
-            { AppTheme.Classic, ("#E8E8E8", "#000000") }
-        };
 
         public MainWindow()
         {
             InitializeComponent();
-            Instance = this; // Set the static reference
             mainContent = this.FindControl<ContentControl>("MainContent");
             ShowLandingPage();
         }
 
+        /// <summary>
+        /// Zeigt die Landing Page an
+        /// </summary>
         public void ShowLandingPage()
         {
-            mainContent!.Content = new LandingPage();
+            if (mainContent != null)
-            Dispatcher.UIThread.Post(() => UpdateTheme(CurrentTheme), DispatcherPriority.Loaded);
+            {
+                mainContent.Content = new LandingPage();
+                Logger.Log("Landing Page angezeigt");
+            }
         }
 
+        /// <summary>
+        /// Zeigt das Periodensystem an
+        /// </summary>
         public void ShowPeriodicTable()
         {
             Logger.Log("ShowPeriodicTable called");
             try
             {
-                mainContent!.Content = new PeriodicTablePage();
+                if (mainContent != null)
-                Logger.Log("PeriodicTablePage created and set");
+                {
-                Dispatcher.UIThread.Post(() => UpdateTheme(CurrentTheme), DispatcherPriority.Loaded);
+                    mainContent.Content = new PeriodicTablePage();
-                Logger.Log("Theme update posted");
+                    Logger.Log("PeriodicTablePage created and set");
+                }
             }
-            catch (Exception ex)
+            catch (System.Exception ex)
             {
                 Logger.Log($"Error in ShowPeriodicTable: {ex.Message}");
             }
         }
 
+        /// <summary>
+        /// Zeigt die About Page an
+        /// </summary>
         public void ShowAboutPage()
         {
-            mainContent!.Content = new AboutPage();
+            if (mainContent != null)
-            Dispatcher.UIThread.Post(() => UpdateTheme(CurrentTheme), DispatcherPriority.Loaded);
-        }
-
-        public void UpdateTheme(AppTheme theme)
-        {
-            CurrentTheme = theme;
-            if (mainContent?.Content is UserControl control)
             {
-                var (background, foreground) = ThemeColors[theme];
+                mainContent.Content = new AboutPage();
-                control.Background = new SolidColorBrush(Color.Parse(background));
+                Logger.Log("About Page angezeigt");
-                
-                // For PeriodicTablePage, use a timer to ensure visual tree is ready
-                if (control is PeriodicTablePage)
-                {
-                    // Wait a bit longer for the visual tree to be fully constructed
-                    var timer = new System.Timers.Timer(100); // 100ms delay
-                    timer.Elapsed += (sender, e) =>
-                    {
-                        timer.Stop();
-                        timer.Dispose();
-                        
-                        Dispatcher.UIThread.Post(() =>
-                        {
-                            try
-                            {
-                                var allButtons = control.GetVisualDescendants().OfType<Button>().ToList();
-                                Logger.Log($"Timer: Found {allButtons.Count} buttons in PeriodicTablePage");
-                                
-                                foreach (var button in allButtons)
-                                {
-                                    // Skip navigation buttons
-                                    if ((button.Width == 250 && button.Height == 40) || 
-                                        (button.Width == 200 && button.Height == 40))
-                                    {
-                                        continue;
-                                    }
-                                    
-                                    // Force white text for element tiles
-                                    button.Foreground = new SolidColorBrush(Colors.WhiteSmoke);
-                                    
-                                    // Force white for TextBlocks inside
-                                    var buttonTextBlocks = button.GetVisualDescendants().OfType<TextBlock>().ToList();
-                                    foreach (var tb in buttonTextBlocks)
-                                    {
-                                        tb.Foreground = new SolidColorBrush(Colors.White);
-                                        Logger.Log($"Timer: Set element tile text to white: '{tb.Text}'");
-                                    }
-                                }
-                            }
-                            catch (Exception ex)
-                            {
-                                Logger.Log($"Timer error: {ex.Message}");
-                            }
-                        });
-                    };
-                    timer.Start();
-                }
-                
-                // Update regular text colors
-                var textBlocks = control.GetVisualDescendants().OfType<TextBlock>().ToList();
-                foreach (var textBlock in textBlocks)
-                {
-                    var parent = textBlock.Parent;
-                    if (parent is Button)
-                        continue;
-                    textBlock.Foreground = new SolidColorBrush(Color.Parse(foreground));
-                }
             }
         }
-
-        private bool IsElementTileButton(Button button)
-        {
-            // Check if this button has element-related content or styling
-            if (button.Content is StackPanel stackPanel)
-            {
-                var textBlocks = stackPanel.Children.OfType<TextBlock>().ToList();
-                if (textBlocks.Count >= 2) // Element tiles typically have symbol and number
-                {
-                    return true;
-                }
-            }
-            
-            // Check if button content is directly a TextBlock with short text
-            if (button.Content is TextBlock textBlock && 
-                textBlock.Text?.Length <= 3)
-            {
-                return true;
-            }
-            
-            return false;
-        }
     }
 }

Project_Periodensystem.View/PeriodicTablePage.axaml

@@ -193,20 +193,33 @@
                 <ColumnDefinition Width="Auto"/>
                 <ColumnDefinition Width="*"/>
                 <ColumnDefinition Width="Auto"/>
+                <ColumnDefinition Width="*"/>
+                <ColumnDefinition Width="Auto"/>
             </Grid.ColumnDefinitions>
                 
-            <Button Name="ThemeButton"
+            <Button Name="BackButton"
                     Grid.Column="0"
+                    Click="BackButton_Click"
+                    Width="200"
+                    Height="40">
+                <TextBlock Text="← Zurück"
+                          FontSize="16"
+                          HorizontalAlignment="Center"/>
+            </Button>
+
+            <Button Name="ThemeButton"
+                    Grid.Column="2"
                     Click="ThemeButton_Click"
                     Width="250"
-                    Height="40">
+                    Height="40"
+                    HorizontalAlignment="Center">
                 <TextBlock Text="Theme wechseln"
                           FontSize="16"
                           HorizontalAlignment="Center"/>
             </Button>
 
             <Button x:Name="AboutButton"
-                    Grid.Column="2"
+                    Grid.Column="4"
                     Click="AboutButton_Click"
                     Width="200"
                     Height="40">

Project_Periodensystem.View/PeriodicTablePage.axaml.cs

@@ -1,10 +1,9 @@
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
-using Avalonia.Markup.Xaml;
 using Avalonia.Media;
-using Project_Periodensystem.Model;  // ElementModel should be here
+using Project_Periodensystem.Controller;
-using Project_Periodensystem.Persistence;
+using Project_Periodensystem.Model;
 using Project_Periodensystem.View.Converters;
 using System;
 using System.Globalization;
@@ -12,92 +11,105 @@ using System.Linq;
 
 namespace Project_Periodensystem.View
 {
+    /// <summary>
+    /// Code-Behind für das Periodensystem - nur UI-Logik, keine Geschäftslogik
+    /// </summary>
     public partial class PeriodicTablePage : UserControl
     {
         private readonly Grid? periodicGrid;
+        private readonly PeriodensystemController _controller;
 
+        /// <summary>
+        /// Konstruktor - initialisiert UI und Controller
+        /// </summary>
         public PeriodicTablePage()
         {
             InitializeComponent();
-            periodicGrid = this.Find<Grid>("PeriodicGrid");
+            
-            InitializePeriodicTable();
+            // Controller initialisieren (MVC-Pattern)
+            _controller = new PeriodensystemController();
+            
+            // Grid-Referenz für Element-Buttons
+            periodicGrid = this.FindControl<Grid>("PeriodicGrid");
+            
+            // Elemente laden und anzeigen
+            LoadAndDisplayElements();
         }
 
-        private void InitializeComponent()
+        /// <summary>
-        {
+        /// Lädt Elemente über Controller und zeigt sie an
-            AvaloniaXamlLoader.Load(this);
+        /// </summary>
-        }
+        private void LoadAndDisplayElements()
-
-        private void InitializePeriodicTable()
         {
             try
             {
-                Logger.Log("Initialisiere PeriodicTable...");
+                // Daten über Controller laden (nicht direkt!)
+                var elements = _controller.GetAllElements();
                 
-                // Prüfen ob das Grid gefunden wurde
+                if (!elements.Any())
-                if (periodicGrid == null)
                 {
-                    Logger.Log("FEHLER: PeriodicGrid nicht gefunden!");
+                    Logger.Log("Keine Elemente vom Controller erhalten");
                     return;
                 }
 
-                // Prüfen ob Elemente vorhanden sind
+                // Datenvalidierung über Controller
-                if (PeriodicTableData.Elements == null || !PeriodicTableData.Elements.Any())
+                if (!_controller.ValidateData())
                 {
-                    Logger.Log("FEHLER: Keine Elemente in PeriodicTableData!");
+                    Logger.Log("Datenvalidierung fehlgeschlagen");
                     return;
                 }
 
-                // Debug: Alle Elemente ausgeben
+                Logger.Log($"Lade {elements.Count} Elemente in das Grid");
-                Logger.Log($"Anzahl Elemente: {PeriodicTableData.Elements.Count()}");
+
-                var firstFew = PeriodicTableData.Elements.Take(5);
+                // UI-Update für jedes Element
-                foreach (var el in firstFew)
+                int successCount = 0;
+                foreach (var element in elements)
                 {
-                    Logger.Log($"Element: {el.Symbol} - Row: {el.Row}, Column: {el.Column}");
+                    if (_controller.ValidateElementPosition(element))
+                    {
+                        CreateElementButton(element);
+                        successCount++;
+                    }
+                    else
+                    {
+                        Logger.Log($"Element {element?.Symbol ?? "NULL"} übersprungen - ungültige Position");
+                    }
                 }
 
-                // Speziell nach H und He suchen
+                Logger.Log($"{successCount} von {elements.Count} Elementen erfolgreich geladen");
-                var hydrogen = PeriodicTableData.Elements.FirstOrDefault(e => e.Symbol == "H");
-                var helium = PeriodicTableData.Elements.FirstOrDefault(e => e.Symbol == "He");
-                
-                if (hydrogen != null)
-                    Logger.Log($"Wasserstoff gefunden: Row {hydrogen.Row}, Column {hydrogen.Column}");
-                else
-                    Logger.Log("Wasserstoff NICHT gefunden!");
-                    
-                if (helium != null)
-                    Logger.Log($"Helium gefunden: Row {helium.Row}, Column {helium.Column}");
-                else
-                    Logger.Log("Helium NICHT gefunden!");
-
-                // Elemente hinzufügen
-                foreach (var element in PeriodicTableData.Elements)
-                {
-                    Logger.Log($"Füge Element hinzu: {element.Symbol} ({element.Row},{element.Column})");
-                    CreateElementButton(element);
-                }
-
-                Logger.Log("PeriodicTable wurde initialisiert");
             }
             catch (Exception ex)
             {
-                Logger.Log($"FEHLER beim Initialisieren des PeriodicTable: {ex.Message}");
+                Logger.Log($"EXCEPTION in LoadAndDisplayElements: {ex.Message}");
-                Logger.Log($"StackTrace: {ex.StackTrace}");
             }
         }
 
+        /// <summary>
+        /// Erstellt UI-Button für ein Element (nur View-Logik)
+        /// </summary>
+        /// <param name="element">Element für das der Button erstellt wird</param>
         private void CreateElementButton(Element element)
         {
+            if (element == null)
+            {
+                Logger.Log("Null-Element kann nicht angezeigt werden");
+                return;
+            }
+
+            // UI-Komponenten erstellen
             var button = new Button { Classes = { "ElementTile" } };
             var panel = new StackPanel();
 
-            // Set background color based on element series
+            // Hintergrundfarbe über Converter setzen
-            var backgroundColor = new SeriesToColorConverter().Convert(element.Series, typeof(Brush), null, CultureInfo.InvariantCulture) as Brush;
+            var backgroundColor = new SeriesToColorConverter()
+                .Convert(element.Series, typeof(Brush), null, CultureInfo.InvariantCulture) as Brush;
+            
             if (backgroundColor != null)
             {
                 button.Background = backgroundColor;
             }
 
+            // Text-Elemente erstellen
             var symbolText = new TextBlock 
             { 
                 Text = element.Symbol,
@@ -114,46 +126,96 @@ namespace Project_Periodensystem.View
                 HorizontalAlignment = Avalonia.Layout.HorizontalAlignment.Center
             };
             
+            // Layout zusammenbauen
             panel.Children.Add(numberText);  // Number on top
             panel.Children.Add(symbolText);  // Symbol below
             button.Content = panel;
 
-            // FIX: Korrekte Grid-Positionierung ohne Math.Max für Spalten!
+            // Grid-Position setzen (0-basiert)
-            int gridRow = element.Row;     // Row direkt verwenden (0-basiert)
+            int gridRow = element.Row;
-            int gridColumn = element.Column; // Column direkt verwenden (0-basiert)
+            int gridColumn = element.Column;
             
-            Logger.Log($"Element {element.Symbol}: Original({element.Row},{element.Column}) -> Grid({gridRow},{gridColumn})");
+            Logger.Log($"Element {element.Symbol}: Grid({gridRow},{gridColumn})");
             
             Grid.SetRow(button, gridRow);
             Grid.SetColumn(button, gridColumn);
             
+            // Button zum Grid hinzufügen
             if (periodicGrid != null)
             {
                 periodicGrid.Children.Add(button);
-                Logger.Log($"Element {element.Symbol} wurde zum Grid hinzugefügt an Position ({gridRow},{gridColumn})");
+            }
+            else
+            {
+                Logger.Log("PeriodicGrid ist null - Button kann nicht hinzugefügt werden");
             }
         }
 
+        /// <summary>
+        /// Event-Handler für Theme-Button
+        /// </summary>
         private void ThemeButton_Click(object? sender, RoutedEventArgs e)
         {
-            var nextTheme = MainWindow.CurrentTheme switch
+            try
             {
-                AppTheme.Dark => AppTheme.Light,
+                // Theme-Wechsel über Application
-                AppTheme.Light => AppTheme.Classic,
+                var app = Application.Current;
-                _ => AppTheme.Dark
+                if (app != null)
-            };
+                {
+                    var currentTheme = app.ActualThemeVariant;
+                    app.RequestedThemeVariant = currentTheme == Avalonia.Styling.ThemeVariant.Dark 
+                        ? Avalonia.Styling.ThemeVariant.Light 
+                        : Avalonia.Styling.ThemeVariant.Dark;
                     
-            if (this.Parent is ContentControl content && content.Parent is MainWindow mainWindow)
+                    Logger.Log($"Theme gewechselt zu: {app.RequestedThemeVariant}");
+                }
+            }
+            catch (Exception ex)
             {
-                mainWindow.UpdateTheme(nextTheme);
+                Logger.Log($"Fehler beim Theme-Wechsel: {ex.Message}");
             }
         }
 
+        /// <summary>
+        /// Event-Handler für About-Button
+        /// </summary>
         private void AboutButton_Click(object? sender, RoutedEventArgs e)
         {
-            if (this.Parent is ContentControl content && content.Parent is MainWindow mainWindow)
+            try
             {
-                mainWindow.ShowAboutPage();
+                // Navigation zur About-Seite
+                var mainWindow = TopLevel.GetTopLevel(this) as Window;
+                if (mainWindow != null)
+                {
+                    var aboutPage = new AboutPage();
+                    mainWindow.Content = aboutPage;
+                    Logger.Log("Navigation zur About-Seite");
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.Log($"Fehler bei Navigation zu About: {ex.Message}");
+            }
+        }
+
+        /// <summary>
+        /// Event-Handler für Zurück-Button (falls gewünscht)
+        /// </summary>
+        private void BackButton_Click(object? sender, RoutedEventArgs e)
+        {
+            try
+            {
+                var mainWindow = TopLevel.GetTopLevel(this) as Window;
+                if (mainWindow != null)
+                {
+                    var landingPage = new LandingPage();
+                    mainWindow.Content = landingPage;
+                    Logger.Log("Navigation zurück zur Landing Page");
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.Log($"Fehler bei Navigation zurück: {ex.Message}");
             }
         }
     }