feat: theme customization with Dark/Light/Custom presets and persistence

CHANGELOG.md

@@ -6,6 +6,21 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+## [1.13.0] - 2026-05-27
+
+### Added
+- **Theme customization** — persistent appearance settings with Dark/Light/Custom modes.
+  Choose from 12 curated presets (6 dark, 6 light) or fully customize accent, background,
+  surface, and text colors. Settings saved between sessions.
+- **Theme button** — palette icon in top-right corner, accessible from every page.
+- **Background shade slider** — fine-tune lightness/darkness within any preset.
+- **Auto companion preset** — switching Dark↔Light automatically selects the matching
+  color family (e.g. Midnight Indigo ↔ Clean Indigo).
+
+### Changed
+- All color resources converted from `StaticResource` to `DynamicResource` for live
+  theme switching without restart.
+
 ## [1.12.1] - 2026-05-27
 
 ### Fixed

SysManager/SysManager/App.xaml.cs

@@ -76,6 +76,8 @@ protected override void OnStartup(StartupEventArgs e)
         TaskScheduler.UnobservedTaskException += OnTask;
         base.OnStartup(e);
 
+        ThemeService.Instance.Initialize();
+
         // Start listening for activation requests from subsequent instances
         StartPipeListener();
     }

SysManager/SysManager/MainWindow.xaml.cs

@@ -133,4 +133,11 @@ protected override void OnClosed(EventArgs e)
         (DataContext as MainWindowViewModel)?.Dispose();
         base.OnClosed(e);
     }
+
+    private void ThemeBtn_Click(object sender, MouseButtonEventArgs e)
+    {
+        if (ThemePopupHost.Child is null)
+            ThemePopupHost.Child = new Views.ThemePopup();
+        ThemePopupHost.IsOpen = !ThemePopupHost.IsOpen;
+    }
 }

SysManager/SysManager/Services/ThemeService.cs

@@ -0,0 +1,310 @@
+// SysManager · ThemeService — runtime theme switching with persistence
+// Author: laurentiu021 · https://github.com/laurentiu021/SystemManager
+// License: MIT
+
+using System.IO;
+using System.Text.Json;
+using System.Windows;
+using System.Windows.Media;
+
+namespace SysManager.Services;
+
+public sealed class ThemeService
+{
+    private static ThemeService? _instance;
+    public static ThemeService Instance => _instance ??= new ThemeService();
+
+    private static readonly string SettingsPath = Path.Combine(
+        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
+        "SysManager", "theme.json");
+
+    public event Action? ThemeChanged;
+
+    public ThemePreset CurrentTheme { get; private set; } = ThemePreset.Defaults["midnight-indigo"];
+    public string CurrentPresetId { get; private set; } = "midnight-indigo";
+    public string CurrentMode { get; private set; } = "dark";
+    public double ShadePosition { get; private set; } = 0.5;
+
+    private ThemePreset _baseTheme = ThemePreset.Defaults["midnight-indigo"];
+
+    private static readonly Dictionary<string, string> DarkToLight = new()
+    {
+        ["midnight-indigo"] = "clean-indigo",
+        ["deep-ocean"] = "sky-breeze",
+        ["dark-forest"] = "mint-fresh",
+        ["neon-rose"] = "soft-blossom",
+        ["violet-night"] = "lavender",
+        ["warm-ember"] = "warm-sand",
+    };
+
+    private static readonly Dictionary<string, string> LightToDark =
+        DarkToLight.ToDictionary(kv => kv.Value, kv => kv.Key);
+
+    private ThemeService() { }
+
+    public void Initialize()
+    {
+        Load();
+        Apply(CurrentTheme);
+    }
+
+    public string GetCompanionPreset(string targetMode)
+    {
+        if (targetMode == "dark" && LightToDark.TryGetValue(CurrentPresetId, out var darkId))
+            return darkId;
+        if (targetMode == "light" && DarkToLight.TryGetValue(CurrentPresetId, out var lightId))
+            return lightId;
+        return targetMode == "dark" ? "midnight-indigo" : "clean-indigo";
+    }
+
+    public void SetPreset(string id)
+    {
+        if (!ThemePreset.Defaults.TryGetValue(id, out var preset)) return;
+        CurrentPresetId = id;
+        _baseTheme = preset;
+        CurrentMode = preset.IsDark ? "dark" : "light";
+        ApplyShade();
+        Save();
+    }
+
+    public void SetAccent(Color accent)
+    {
+        _baseTheme = _baseTheme with { Accent = accent };
+        ApplyShade();
+        Save();
+    }
+
+    public void SetShade(double position)
+    {
+        ShadePosition = Math.Clamp(position, 0, 1);
+        ApplyShade();
+        Save();
+    }
+
+    public void SetCustom(Color accent, Color background, Color surface, Color text)
+    {
+        CurrentMode = "custom";
+        CurrentPresetId = "custom";
+        _baseTheme = new ThemePreset(
+            Id: "custom",
+            Name: "Custom",
+            IsDark: background.R + background.G + background.B < 384,
+            Accent: accent,
+            Background: background,
+            Surface: surface,
+            Surface2: Lerp(surface, background, 0.5),
+            Border: Lerp(surface, text, 0.15),
+            TextPrimary: text,
+            TextSecondary: Lerp(text, background, 0.3),
+            TextMuted: Lerp(text, background, 0.55));
+        CurrentTheme = new ThemePreset(
+            Id: "custom",
+            Name: "Custom",
+            IsDark: background.R + background.G + background.B < 384,
+            Accent: accent,
+            Background: background,
+            Surface: surface,
+            Surface2: Lerp(surface, background, 0.5),
+            Border: Lerp(surface, text, 0.15),
+            TextPrimary: text,
+            TextSecondary: Lerp(text, background, 0.3),
+            TextMuted: Lerp(text, background, 0.55));
+        Apply(CurrentTheme);
+        Save();
+    }
+
+    private void ApplyShade()
+    {
+        var t = _baseTheme;
+        var offset = (ShadePosition - 0.5) * 0.12;
+
+        CurrentTheme = t with
+        {
+            Background = ShiftLightness(t.Background, offset),
+            Surface = ShiftLightness(t.Surface, offset),
+            Surface2 = ShiftLightness(t.Surface2, offset),
+            Border = ShiftLightness(t.Border, offset)
+        };
+        Apply(CurrentTheme);
+    }
+
+    public void Apply(ThemePreset theme)
+    {
+        var res = Application.Current.Resources;
+        SetBrush(res, "Surface0", theme.Background);
+        SetBrush(res, "Surface1", theme.Surface);
+        SetBrush(res, "Surface2", theme.Surface2);
+        SetBrush(res, "Surface3", Lerp(theme.Surface2, theme.TextPrimary, 0.05));
+        SetBrush(res, "Surface4", Lerp(theme.Surface2, theme.TextPrimary, 0.1));
+        SetBrush(res, "Border1", theme.Border);
+        SetBrush(res, "Border2", Lerp(theme.Border, theme.TextPrimary, 0.08));
+        SetBrush(res, "BorderAccent", Lerp(theme.Border, theme.Accent, 0.2));
+        SetBrush(res, "TextPrimary", theme.TextPrimary);
+        SetBrush(res, "TextSecondary", theme.TextSecondary);
+        SetBrush(res, "TextMuted", theme.TextMuted);
+        SetBrush(res, "TextDisabled", Lerp(theme.TextMuted, theme.Background, 0.4));
+        SetBrush(res, "Accent", theme.Accent);
+        SetBrush(res, "AccentHover", Lighten(theme.Accent, 0.15));
+        SetBrush(res, "AccentPressed", Darken(theme.Accent, 0.12));
+        SetBrush(res, "AccentSoft", Color.FromArgb(15, theme.Accent.R, theme.Accent.G, theme.Accent.B));
+
+        SetColor(res, "Surface0Color", theme.Background);
+        SetColor(res, "Surface1Color", theme.Surface);
+        SetColor(res, "Surface2Color", theme.Surface2);
+        SetColor(res, "Surface3Color", Lerp(theme.Surface2, theme.TextPrimary, 0.05));
+        SetColor(res, "Surface4Color", Lerp(theme.Surface2, theme.TextPrimary, 0.1));
+        SetColor(res, "AccentColor", theme.Accent);
+        SetColor(res, "AccentHoverColor", Lighten(theme.Accent, 0.15));
+        SetColor(res, "AccentPressedColor", Darken(theme.Accent, 0.12));
+
+        ThemeChanged?.Invoke();
+    }
+
+    private static void SetBrush(ResourceDictionary res, string key, Color color)
+    {
+        res[key] = new SolidColorBrush(color);
+    }
+
+    private static void SetColor(ResourceDictionary res, string key, Color color)
+    {
+        res[key] = color;
+    }
+
+    private static Color Lerp(Color a, Color b, double t)
+    {
+        return Color.FromArgb(
+            (byte)(a.A + (b.A - a.A) * t),
+            (byte)(a.R + (b.R - a.R) * t),
+            (byte)(a.G + (b.G - a.G) * t),
+            (byte)(a.B + (b.B - a.B) * t));
+    }
+
+    private static Color Lighten(Color c, double amount)
+    {
+        return Color.FromArgb(c.A,
+            (byte)Math.Min(255, c.R + (255 - c.R) * amount),
+            (byte)Math.Min(255, c.G + (255 - c.G) * amount),
+            (byte)Math.Min(255, c.B + (255 - c.B) * amount));
+    }
+
+    private static Color Darken(Color c, double amount)
+    {
+        return Color.FromArgb(c.A,
+            (byte)(c.R * (1 - amount)),
+            (byte)(c.G * (1 - amount)),
+            (byte)(c.B * (1 - amount)));
+    }
+
+    private static Color ShiftLightness(Color c, double amount)
+    {
+        if (amount >= 0)
+            return Lighten(c, amount);
+        return Darken(c, -amount);
+    }
+
+    private void Save()
+    {
+        try
+        {
+            var dir = Path.GetDirectoryName(SettingsPath)!;
+            Directory.CreateDirectory(dir);
+            var data = new ThemeSettings(CurrentPresetId, CurrentMode, ShadePosition,
+                CurrentTheme.Accent.ToString(), CurrentTheme.Background.ToString(),
+                CurrentTheme.Surface.ToString(), CurrentTheme.TextPrimary.ToString());
+            var json = JsonSerializer.Serialize(data, new JsonSerializerOptions { WriteIndented = true });
+            File.WriteAllText(SettingsPath, json);
+        }
+        catch { }
+    }
+
+    private void Load()
+    {
+        try
+        {
+            if (!File.Exists(SettingsPath)) return;
+            var json = File.ReadAllText(SettingsPath);
+            var data = JsonSerializer.Deserialize<ThemeSettings>(json);
+            if (data is null) return;
+
+            CurrentMode = data.Mode;
+            ShadePosition = data.ShadePosition;
+            CurrentPresetId = data.PresetId;
+
+            if (data.PresetId == "custom")
+            {
+                var accent = (Color)ColorConverter.ConvertFromString(data.Accent);
+                var bg = (Color)ColorConverter.ConvertFromString(data.Background);
+                var surface = (Color)ColorConverter.ConvertFromString(data.Surface);
+                var text = (Color)ColorConverter.ConvertFromString(data.Text);
+                SetCustom(accent, bg, surface, text);
+            }
+            else if (ThemePreset.Defaults.TryGetValue(data.PresetId, out var preset))
+            {
+                _baseTheme = preset;
+                CurrentTheme = preset;
+                ApplyShade();
+            }
+        }
+        catch { }
+    }
+
+    private sealed record ThemeSettings(
+        string PresetId, string Mode, double ShadePosition,
+        string Accent, string Background, string Surface, string Text);
+}
+
+public sealed record ThemePreset(
+    string Id,
+    string Name,
+    bool IsDark,
+    Color Accent,
+    Color Background,
+    Color Surface,
+    Color Surface2,
+    Color Border,
+    Color TextPrimary,
+    Color TextSecondary,
+    Color TextMuted)
+{
+    public static readonly Dictionary<string, ThemePreset> Defaults = new()
+    {
+        ["midnight-indigo"] = new("midnight-indigo", "Midnight Indigo", true,
+            C("#6366F1"), C("#070A0F"), C("#0E1218"), C("#151A23"), C("#1F2633"),
+            C("#F1F3F7"), C("#A3ADBF"), C("#6B7489")),
+        ["deep-ocean"] = new("deep-ocean", "Deep Ocean", true,
+            C("#3B82F6"), C("#050D1A"), C("#0A1628"), C("#0F1D33"), C("#1A2D4D"),
+            C("#E2E8F0"), C("#94A3B8"), C("#64748B")),
+        ["dark-forest"] = new("dark-forest", "Dark Forest", true,
+            C("#10B981"), C("#020F0A"), C("#021A12"), C("#03261A"), C("#0A3D2A"),
+            C("#D1FAE5"), C("#6EE7B7"), C("#34D399")),
+        ["neon-rose"] = new("neon-rose", "Neon Rose", true,
+            C("#EC4899"), C("#120508"), C("#1A0A0F"), C("#240E16"), C("#3D1525"),
+            C("#FDF2F8"), C("#F9A8D4"), C("#F472B6")),
+        ["violet-night"] = new("violet-night", "Violet Night", true,
+            C("#A855F7"), C("#0A0515"), C("#0F0A1A"), C("#160F26"), C("#2D1B4E"),
+            C("#F3E8FF"), C("#C4B5FD"), C("#8B5CF6")),
+        ["warm-ember"] = new("warm-ember", "Warm Ember", true,
+            C("#F59E0B"), C("#0F0A04"), C("#1A1008"), C("#24180C"), C("#3D2A12"),
+            C("#FEF3C7"), C("#FCD34D"), C("#FBBF24")),
+        ["clean-indigo"] = new("clean-indigo", "Clean Indigo", false,
+            C("#6366F1"), C("#FFFFFF"), C("#F8FAFC"), C("#F1F5F9"), C("#E2E8F0"),
+            C("#1E1B4B"), C("#4338CA"), C("#6366F1")),
+        ["sky-breeze"] = new("sky-breeze", "Sky Breeze", false,
+            C("#0EA5E9"), C("#F8FAFC"), C("#F0F9FF"), C("#E0F2FE"), C("#BAE6FD"),
+            C("#0C4A6E"), C("#0369A1"), C("#0284C7")),
+        ["warm-sand"] = new("warm-sand", "Warm Sand", false,
+            C("#D97706"), C("#FFFBEB"), C("#FEF3C7"), C("#FDE68A"), C("#FCD34D"),
+            C("#451A03"), C("#78350F"), C("#92400E")),
+        ["mint-fresh"] = new("mint-fresh", "Mint Fresh", false,
+            C("#16A34A"), C("#F0FDF4"), C("#DCFCE7"), C("#BBF7D0"), C("#86EFAC"),
+            C("#14532D"), C("#166534"), C("#15803D")),
+        ["soft-blossom"] = new("soft-blossom", "Soft Blossom", false,
+            C("#DB2777"), C("#FDF2F8"), C("#FCE7F3"), C("#FBCFE8"), C("#F9A8D4"),
+            C("#500724"), C("#831843"), C("#9D174D")),
+        ["lavender"] = new("lavender", "Lavender", false,
+            C("#7C3AED"), C("#FAF5FF"), C("#F3E8FF"), C("#E9D5FF"), C("#D8B4FE"),
+            C("#2E1065"), C("#4C1D95"), C("#5B21B6")),
+    };
+
+    private static Color C(string hex) => (Color)ColorConverter.ConvertFromString(hex);
+}