Fixes

main/WidgetConfig.cpp

@@ -164,6 +164,9 @@ void WidgetConfig::serialize(uint8_t* buf) const {
     buf[pos++] = arcValueColor.g;
     buf[pos++] = arcValueColor.b;
     buf[pos++] = arcValueFontSize;
+
+    // Theme
+    buf[pos++] = themeFixed ? 1 : 0;
 }
 
 void WidgetConfig::deserialize(const uint8_t* buf) {
@@ -376,6 +379,13 @@ void WidgetConfig::deserialize(const uint8_t* buf) {
         arcValueColor = textColor;
         arcValueFontSize = fontSize;
     }
+
+    // Theme
+    if (pos + 1 <= SERIALIZED_SIZE) {
+        themeFixed = buf[pos++] != 0;
+    } else {
+        themeFixed = false;
+    }
 }
 
 WidgetConfig WidgetConfig::createLabel(uint8_t id, int16_t x, int16_t y, const char* labelText) {
@@ -408,6 +418,7 @@ WidgetConfig WidgetConfig::createLabel(uint8_t id, int16_t x, int16_t y, const c
     cfg.arcScaleColor = cfg.textColor;
     cfg.arcValueColor = cfg.textColor;
     cfg.arcValueFontSize = cfg.fontSize;
+    cfg.themeFixed = false;
     cfg.shadow.enabled = false;
     // Icon defaults
     cfg.iconCodepoint = 0;
@@ -469,6 +480,7 @@ WidgetConfig WidgetConfig::createButton(uint8_t id, int16_t x, int16_t y,
     cfg.arcScaleColor = cfg.textColor;
     cfg.arcValueColor = cfg.textColor;
     cfg.arcValueFontSize = cfg.fontSize;
+    cfg.themeFixed = false;
     cfg.shadow.enabled = true;
     cfg.shadow.offsetX = 2;
     cfg.shadow.offsetY = 2;
@@ -507,6 +519,7 @@ void ScreenConfig::clear(uint8_t newId, const char* newName) {
     id = newId;
     mode = ScreenMode::FULLSCREEN;
     backgroundColor = {26, 26, 46}; // Dark blue background
+    nightBackgroundColor = {14, 18, 23}; // Darker night background
     bgImagePath[0] = '\0';          // No background image
     bgImageMode = BgImageMode::STRETCH;
     widgetCount = 0;

main/WidgetConfig.hpp

@@ -107,6 +107,49 @@ struct Color {
             .b = static_cast<uint8_t>(hex & 0xFF)
         };
     }
+
+    // Invert lightness via HSL: light colors become dark, dark become light
+    Color invertLightness() const {
+        float rf = r / 255.0f, gf = g / 255.0f, bf = b / 255.0f;
+        float maxC = rf > gf ? (rf > bf ? rf : bf) : (gf > bf ? gf : bf);
+        float minC = rf < gf ? (rf < bf ? rf : bf) : (gf < bf ? gf : bf);
+        float delta = maxC - minC;
+        float L = (maxC + minC) * 0.5f;
+        float S = 0.0f, H = 0.0f;
+        if (delta > 0.0001f) {
+            S = L < 0.5f ? delta / (maxC + minC) : delta / (2.0f - maxC - minC);
+            if (maxC == rf)      H = (gf - bf) / delta + (gf < bf ? 6.0f : 0.0f);
+            else if (maxC == gf) H = (bf - rf) / delta + 2.0f;
+            else                 H = (rf - gf) / delta + 4.0f;
+            H /= 6.0f;
+        }
+        // Invert lightness
+        L = 1.0f - L;
+        // HSL to RGB
+        auto hue2rgb = [](float p, float q, float t) -> float {
+            if (t < 0.0f) t += 1.0f;
+            if (t > 1.0f) t -= 1.0f;
+            if (t < 1.0f / 6.0f) return p + (q - p) * 6.0f * t;
+            if (t < 0.5f) return q;
+            if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6.0f;
+            return p;
+        };
+        float ro, go, bo;
+        if (S < 0.0001f) {
+            ro = go = bo = L;
+        } else {
+            float q = L < 0.5f ? L * (1.0f + S) : L + S - L * S;
+            float p = 2.0f * L - q;
+            ro = hue2rgb(p, q, H + 1.0f / 3.0f);
+            go = hue2rgb(p, q, H);
+            bo = hue2rgb(p, q, H - 1.0f / 3.0f);
+        }
+        return {
+            .r = static_cast<uint8_t>(ro * 255.0f + 0.5f),
+            .g = static_cast<uint8_t>(go * 255.0f + 0.5f),
+            .b = static_cast<uint8_t>(bo * 255.0f + 0.5f)
+        };
+    }
 };
 
 // Condition operator for conditional styling
@@ -298,9 +341,11 @@ struct WidgetConfig {
     Color arcValueColor;      // Center value text color
     uint8_t arcValueFontSize; // Center value font size index
 
+    // Theme
+    bool themeFixed;          // true = colors stay fixed in night mode
+
     // Serialization size (fixed for NVS storage)
-    // 369 + 36 (6 subbuttons * 6 bytes for icon colors) = 405
+    static constexpr size_t SERIALIZED_SIZE = 406;
-    static constexpr size_t SERIALIZED_SIZE = 405;
 
     void serialize(uint8_t* buf) const;
     void deserialize(const uint8_t* buf);
@@ -323,6 +368,7 @@ struct ScreenConfig {
     char name[MAX_SCREEN_NAME_LEN];
     ScreenMode mode;
     Color backgroundColor;
+    Color nightBackgroundColor;  // Background color for night mode
     char bgImagePath[MAX_BG_IMAGE_PATH_LEN];  // Background image path (e.g., "/images/bg.png")
     BgImageMode bgImageMode;                   // 0=none, 1=stretch, 2=center, 3=tile
     uint8_t widgetCount;

main/WidgetManager.cpp

@@ -1137,6 +1137,22 @@ void WidgetManager::refreshChartWidgets() {
     refreshChartWidgetsLocked();
 }
 
+void WidgetManager::applyNightMode(bool night) {
+    // Update screen background
+    const ScreenConfig* screen = activeScreen();
+    if (screen && screen_) {
+        Color bg = night ? screen->nightBackgroundColor : screen->backgroundColor;
+        lv_obj_set_style_bg_color(screen_, lv_color_make(bg.r, bg.g, bg.b), 0);
+    }
+
+    // Re-apply style to all widgets (they check nightMode_ internally)
+    for (auto& widget : widgets_) {
+        if (widget) {
+            widget->applyStyle();
+        }
+    }
+}
+
 void WidgetManager::updateSystemTimeWidgets() {
     int64_t nowUs = esp_timer_get_time();
     if (nowUs - lastSystemTimeUpdateUs_ < 500000) { // Update every 500ms
@@ -1222,7 +1238,10 @@ void WidgetManager::applyKnxSwitch(uint16_t groupAddr, bool value) {
     }
 
     if (config_->knxNightModeAddress != 0 && groupAddr == config_->knxNightModeAddress) {
-        nightMode_ = value;
+        if (nightMode_ != value) {
+            nightMode_ = value;
+            applyNightMode(value);
+        }
     }
 }
 
@@ -1545,6 +1564,11 @@ void WidgetManager::getConfigJson(char* buf, size_t bufSize) const {
                  screen.backgroundColor.r, screen.backgroundColor.g, screen.backgroundColor.b);
         cJSON_AddStringToObject(screenJson, "bgColor", bgColorStr);
 
+        char nightBgColorStr[8];
+        snprintf(nightBgColorStr, sizeof(nightBgColorStr), "#%02X%02X%02X",
+                 screen.nightBackgroundColor.r, screen.nightBackgroundColor.g, screen.nightBackgroundColor.b);
+        cJSON_AddStringToObject(screenJson, "nightBgColor", nightBgColorStr);
+
         // Background image
         if (screen.bgImagePath[0] != '\0') {
             cJSON_AddStringToObject(screenJson, "bgImage", screen.bgImagePath);
@@ -1638,6 +1662,8 @@ void WidgetManager::getConfigJson(char* buf, size_t bufSize) const {
             cJSON_AddStringToObject(widget, "arcValueColor", arcValueColorStr);
             cJSON_AddNumberToObject(widget, "arcValueFontSize", w.arcValueFontSize);
 
+            cJSON_AddBoolToObject(widget, "themeFixed", w.themeFixed);
+
             cJSON_AddNumberToObject(widget, "parentId", w.parentId);
 
             // Secondary KNX address (left value)
@@ -2004,6 +2030,9 @@ bool WidgetManager::updateConfigFromJson(const char* json) {
             cJSON* arcValueFontSize = cJSON_GetObjectItem(widget, "arcValueFontSize");
             if (cJSON_IsNumber(arcValueFontSize)) w.arcValueFontSize = arcValueFontSize->valueint;
 
+            cJSON* themeFixed = cJSON_GetObjectItem(widget, "themeFixed");
+            if (cJSON_IsBool(themeFixed)) w.themeFixed = cJSON_IsTrue(themeFixed);
+
             cJSON* parentId = cJSON_GetObjectItem(widget, "parentId");
             if (cJSON_IsNumber(parentId)) {
                 w.parentId = static_cast<int8_t>(parentId->valueint);
@@ -2362,6 +2391,11 @@ bool WidgetManager::updateConfigFromJson(const char* json) {
                 screen.backgroundColor = Color::fromHex(parseHexColor(bgColor->valuestring));
             }
 
+            cJSON* nightBgColor = cJSON_GetObjectItem(screenJson, "nightBgColor");
+            if (cJSON_IsString(nightBgColor)) {
+                screen.nightBackgroundColor = Color::fromHex(parseHexColor(nightBgColor->valuestring));
+            }
+
             // Parse background image
             cJSON* bgImage = cJSON_GetObjectItem(screenJson, "bgImage");
             if (cJSON_IsString(bgImage)) {

main/WidgetManager.hpp

@@ -66,6 +66,9 @@ public:
     // KNX write (for RoomCard sub-buttons etc.)
     void sendKnxSwitch(uint16_t groupAddr, bool value);
 
+    // Night mode
+    bool isNightMode() const { return nightMode_; }
+
     // Direct config access
     GuiConfig& getConfig() { return *config_; }
     const GuiConfig& getConfig() const { return *config_; }
@@ -148,6 +151,7 @@ private:
     static bool isNumericTextSource(TextSource source);
     void refreshChartWidgetsLocked();
     void refreshChartWidgets();
+    void applyNightMode(bool night);
 
     void createDefaultConfig();
     void applyScreen(uint8_t screenId);

main/widgets/ArcWidget.cpp

@@ -82,11 +82,12 @@ void ArcWidget::applyStyle() {
     if (arcWidth < 2) arcWidth = 2;
     if (arcWidth > 48) arcWidth = 48;
 
-    lv_color_t trackColor = lv_color_make(config_.bgColor.r, config_.bgColor.g, config_.bgColor.b);
+    Color trackCol = themeColor(config_.bgColor);
+    lv_color_t trackColor = lv_color_make(trackCol.r, trackCol.g, trackCol.b);
     uint8_t trackOpa = config_.bgOpacity > 0 ? config_.bgOpacity : static_cast<uint8_t>(LV_OPA_40);
 
-    lv_color_t indicatorColor = lv_color_make(
+    Color indicatorCol = themeColor(config_.textColor);
-        config_.textColor.r, config_.textColor.g, config_.textColor.b);
+    lv_color_t indicatorColor = lv_color_make(indicatorCol.r, indicatorCol.g, indicatorCol.b);
 
     lv_obj_set_style_arc_width(obj_, arcWidth, LV_PART_MAIN);
     lv_obj_set_style_arc_color(obj_, trackColor, LV_PART_MAIN);
@@ -135,8 +136,8 @@ void ArcWidget::applyStyle() {
         lv_obj_set_style_arc_width(scale_, 1, LV_PART_MAIN);
         lv_obj_set_style_arc_opa(scale_, LV_OPA_TRANSP, LV_PART_MAIN);
 
-        lv_color_t scaleColor = lv_color_make(
+        Color scaleCol = themeColor(config_.arcScaleColor);
-            config_.arcScaleColor.r, config_.arcScaleColor.g, config_.arcScaleColor.b);
+        lv_color_t scaleColor = lv_color_make(scaleCol.r, scaleCol.g, scaleCol.b);
         lv_obj_set_style_line_color(scale_, scaleColor, LV_PART_INDICATOR);
         lv_obj_set_style_line_color(scale_, scaleColor, LV_PART_ITEMS);
         lv_obj_set_style_line_width(scale_, 2, LV_PART_INDICATOR);
@@ -155,8 +156,8 @@ void ArcWidget::applyStyle() {
     }
 
     if (valueLabel_) {
-        lv_color_t valueColor = lv_color_make(
+        Color valueCol = themeColor(config_.arcValueColor);
-            config_.arcValueColor.r, config_.arcValueColor.g, config_.arcValueColor.b);
+        lv_color_t valueColor = lv_color_make(valueCol.r, valueCol.g, valueCol.b);
         lv_obj_set_style_text_color(valueLabel_, valueColor, 0);
         lv_obj_set_style_text_font(valueLabel_, getFontBySize(config_.arcValueFontSize), 0);
         lv_obj_center(valueLabel_);

main/widgets/Widget.cpp

@@ -1,5 +1,6 @@
 #include "Widget.hpp"
 #include "../Fonts.hpp"
+#include "../WidgetManager.hpp"
 #include "lvgl.h"
 
 Widget::Widget(const WidgetConfig& config)
@@ -161,20 +162,30 @@ void Widget::applyConditionStyle(const ConditionStyle& style) {
     }
 }
 
+bool Widget::shouldTransformColors() const {
+    return WidgetManager::instance().isNightMode() && !config_.themeFixed;
+}
+
+Color Widget::themeColor(const Color& c) const {
+    return shouldTransformColors() ? c.invertLightness() : c;
+}
+
 void Widget::applyCommonStyle() {
     if (obj_ == nullptr) return;
 
+    Color textCol = themeColor(config_.textColor);
+    Color bgCol = themeColor(config_.bgColor);
+    Color borderCol = themeColor(config_.borderColor);
+
     // Text color
-    lv_obj_set_style_text_color(obj_, lv_color_make(
+    lv_obj_set_style_text_color(obj_, lv_color_make(textCol.r, textCol.g, textCol.b), 0);
-        config_.textColor.r, config_.textColor.g, config_.textColor.b), 0);
 
     // Font
     lv_obj_set_style_text_font(obj_, getFontBySize(config_.fontSize), 0);
 
     // Background (for buttons and labels with bg)
     if (config_.bgOpacity > 0) {
-        lv_obj_set_style_bg_color(obj_, lv_color_make(
+        lv_obj_set_style_bg_color(obj_, lv_color_make(bgCol.r, bgCol.g, bgCol.b), 0);
-            config_.bgColor.r, config_.bgColor.g, config_.bgColor.b), 0);
         lv_obj_set_style_bg_opa(obj_, config_.bgOpacity, 0);
     }
 
@@ -186,8 +197,7 @@ void Widget::applyCommonStyle() {
     // Border
     if (config_.borderWidth > 0 && config_.borderOpacity > 0) {
         lv_obj_set_style_border_width(obj_, config_.borderWidth, 0);
-        lv_obj_set_style_border_color(obj_, lv_color_make(
+        lv_obj_set_style_border_color(obj_, lv_color_make(borderCol.r, borderCol.g, borderCol.b), 0);
-            config_.borderColor.r, config_.borderColor.g, config_.borderColor.b), 0);
         lv_obj_set_style_border_opa(obj_, config_.borderOpacity, 0);
     } else {
         lv_obj_set_style_border_width(obj_, 0, 0);
@@ -213,8 +223,8 @@ void Widget::applyShadowStyle() {
     if (spread < 0) spread = 0;
     if (blur == 0) return;
 
-    lv_color_t shadowColor = lv_color_make(
+    Color sc = themeColor(config_.shadow.color);
-        config_.shadow.color.r, config_.shadow.color.g, config_.shadow.color.b);
+    lv_color_t shadowColor = lv_color_make(sc.r, sc.g, sc.b);
 
     // Default state shadow
     lv_obj_set_style_shadow_color(obj_, shadowColor, 0);

main/widgets/Widget.hpp

@@ -4,6 +4,8 @@
 #include "lvgl.h"
 #include <ctime>
 
+class WidgetManager;
+
 class Widget {
 public:
     explicit Widget(const WidgetConfig& config);
@@ -70,6 +72,10 @@ protected:
     void applyConditionStyle(const ConditionStyle& style);
     static const lv_font_t* getFontBySize(uint8_t sizeIndex);
 
+    // Night mode color transformation
+    bool shouldTransformColors() const;
+    Color themeColor(const Color& c) const;
+
     const WidgetConfig& config_;
     lv_obj_t* obj_ = nullptr;
 

web-interface/src/components/CanvasArea.vue

@@ -8,6 +8,14 @@
             <span class="text-[11px] text-muted">{{ store.config.screens.length }}</span>
           </div>
           <div class="flex items-center gap-2">
+            <button
+              class="border px-2.5 py-1.5 rounded-[10px] text-[12px] font-semibold transition hover:-translate-y-0.5 active:translate-y-0.5"
+              :class="store.nightPreview ? 'bg-[#2f3b4a] text-white border-[#4a5568]' : 'border-border bg-panel-2 text-text hover:bg-[#e4ebf2]'"
+              @click="store.nightPreview = !store.nightPreview"
+              title="Nachtmodus-Vorschau"
+            >
+              <span class="material-symbols-outlined text-[16px] align-middle">{{ store.nightPreview ? 'dark_mode' : 'light_mode' }}</span>
+            </button>
             <button class="border border-border bg-panel-2 text-text px-2.5 py-1.5 rounded-[10px] text-[12px] font-semibold transition hover:-translate-y-0.5 hover:bg-[#e4ebf2] active:translate-y-0.5" @click="emit('open-screen-settings')">Einstellungen</button>
             <button class="w-7 h-7 rounded-lg border border-border bg-panel-2 text-text grid place-items-center cursor-pointer hover:bg-[#e4ebf2] hover:border-[#b8c4d2]" @click="store.addScreen">+</button>
             <button class="w-7 h-7 rounded-lg border border-border bg-panel-2 text-text grid place-items-center cursor-pointer hover:bg-[#e4ebf2] hover:border-[#b8c4d2]" @click="screensOpen = !screensOpen">
@@ -94,7 +102,9 @@ const canvasStyle = computed(() => {
     const style = {
         width: `${canvasW.value * store.canvasScale}px`,
         height: `${canvasH.value * store.canvasScale}px`,
-        backgroundColor: store.activeScreen?.bgColor || '#1A1A2E'
+        backgroundColor: store.nightPreview
+            ? (store.activeScreen?.nightBgColor || '#0E1217')
+            : (store.activeScreen?.bgColor || '#1A1A2E')
     };
 
     // Add background image if set

web-interface/src/components/ScreenSettingsModal.vue

@@ -16,6 +16,10 @@
             <label class="text-[12px] text-muted">Hintergrund</label>
             <input class="h-[30px] w-[44px] cursor-pointer border-0 bg-transparent p-0" type="color" v-model="screen.bgColor">
           </div>
+          <div class="flex items-center justify-between gap-2.5">
+            <label class="text-[12px] text-muted">Nacht-Hintergrund</label>
+            <input class="h-[30px] w-[44px] cursor-pointer border-0 bg-transparent p-0" type="color" v-model="screen.nightBgColor">
+          </div>
           <div class="flex items-center justify-between gap-2.5">
             <label class="text-[12px] text-muted">Modus</label>
             <select class="flex-1 bg-panel-2 border border-border rounded-lg px-2 py-1.5 text-text text-[12px] focus:outline-none focus:border-accent" v-model.number="screen.mode">

web-interface/src/components/SidebarRight.vue

@@ -13,6 +13,7 @@
         <div :class="rowClass"><label :class="labelClass">Breite</label><input :class="inputClass" type="number" v-model.number="w.w"></div>
         <div :class="rowClass"><label :class="labelClass">Hoehe</label><input :class="inputClass" type="number" v-model.number="w.h"></div>
         <div :class="rowClass"><label :class="labelClass">Sichtbar</label><input class="accent-[var(--accent)]" type="checkbox" v-model="w.visible"></div>
+        <div :class="rowClass"><label :class="labelClass">Farbe fixieren</label><input class="accent-[var(--accent)]" type="checkbox" v-model="w.themeFixed"></div>
 
         <!-- Widget-specific settings -->
         <component

web-interface/src/components/WidgetElement.vue

@@ -1,7 +1,7 @@
 <template>
   <component
     :is="widgetComponent"
-    :widget="widget"
+    :widget="themedWidget"
     :scale="scale"
     :selected="selected"
     @select="$emit('select')"
@@ -12,6 +12,8 @@
 
 <script setup>
 import { computed, markRaw } from 'vue';
+import { useEditorStore } from '../stores/editor';
+import { invertLightness } from '../utils';
 import { WIDGET_TYPES } from '../constants';
 
 // Import all widget element components
@@ -56,7 +58,26 @@ const componentMap = {
   [WIDGET_TYPES.BUTTONMATRIX]: markRaw(ButtonMatrixElement)
 };
 
+const store = useEditorStore();
+
 const widgetComponent = computed(() => {
   return componentMap[props.widget.type] || LabelElement;
 });
+
+const colorKeys = ['textColor', 'bgColor', 'borderColor', 'arcScaleColor', 'arcValueColor'];
+
+const themedWidget = computed(() => {
+  const w = props.widget;
+  if (!store.nightPreview || w.themeFixed) return w;
+  const copy = { ...w };
+  for (const key of colorKeys) {
+    if (copy[key] && typeof copy[key] === 'string' && copy[key].startsWith('#')) {
+      copy[key] = invertLightness(copy[key]);
+    }
+  }
+  if (copy.shadow && copy.shadow.enabled && copy.shadow.color) {
+    copy.shadow = { ...copy.shadow, color: invertLightness(copy.shadow.color) };
+  }
+  return copy;
+});
 </script>

web-interface/src/constants.js

@@ -208,7 +208,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0,
         iconSize: 1,
-        iconGap: 8
+        iconGap: 8,
+        themeFixed: false
     },
     button: {
         w: 130,
@@ -232,6 +233,7 @@ export const WIDGET_DEFAULTS = {
         iconPosition: 0,
         iconSize: 1,
         iconGap: 8,
+        themeFixed: false,
         conditions: []
     },
     led: {
@@ -254,7 +256,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0,
         iconSize: 1,
-        iconGap: 8
+        iconGap: 8,
+        themeFixed: false
     },
     icon: {
         w: 48,
@@ -276,7 +279,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0xe88a,
         iconPosition: 0,
         iconSize: 3,
-        iconGap: 8
+        iconGap: 8,
+        themeFixed: false
     },
     tabview: {
         w: 400,
@@ -298,7 +302,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0, // 0=Top, 1=Bottom, 2=Left, 3=Right
         iconSize: 5, // Used for Tab Height (x10) -> 50px
-        iconGap: 0
+        iconGap: 0,
+        themeFixed: false
     },
     tabpage: {
         w: 0, // Ignored
@@ -320,7 +325,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0,
         iconSize: 1,
-        iconGap: 0
+        iconGap: 0,
+        themeFixed: false
     },
     powerflow: {
         w: 720,
@@ -342,7 +348,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0,
         iconSize: 1,
-        iconGap: 0
+        iconGap: 0,
+        themeFixed: false
     },
     powernode: {
         w: 120,
@@ -374,6 +381,7 @@ export const WIDGET_DEFAULTS = {
         text3: '',
         knxAddr3: 0,
         // Conditions
+        themeFixed: false,
         conditions: []
     },
     powerlink: {
@@ -396,7 +404,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0,
         iconSize: 0,
-        iconGap: 6
+        iconGap: 6,
+        themeFixed: false
     },
     chart: {
         w: 360,
@@ -419,6 +428,7 @@ export const WIDGET_DEFAULTS = {
         iconPosition: 0,
         iconSize: 1,
         iconGap: 0,
+        themeFixed: false,
         chart: {
             period: 0,
             series: [
@@ -446,7 +456,8 @@ export const WIDGET_DEFAULTS = {
         iconCodepoint: 0,
         iconPosition: 0,
         iconSize: 1,
-        iconGap: 0
+        iconGap: 0,
+        themeFixed: false
     },
     roomcard: {
         w: 200,
@@ -474,7 +485,8 @@ export const WIDGET_DEFAULTS = {
         subButtonOpacity: 255, // Sub-button opacity (0-255)
         cardStyle: 0,  // 0=Bubble (round), 1=Tile (rectangular)
         subButtons: [],
-        textLines: []  // Variable text lines with icon, text, textSrc, knxAddr, fontSize
+        textLines: [],  // Variable text lines with icon, text, textSrc, knxAddr, fontSize
+        themeFixed: false
     },
     rectangle: {
         w: 220,
@@ -501,7 +513,8 @@ export const WIDGET_DEFAULTS = {
         iconSize: 1,
         iconGap: 0,
         iconPositionX: 0,
-        iconPositionY: 0
+        iconPositionY: 0,
+        themeFixed: false
     },
     arc: {
         w: 180,
@@ -536,7 +549,8 @@ export const WIDGET_DEFAULTS = {
         iconSize: 1,
         iconGap: 0,
         iconPositionX: 0,
-        iconPositionY: 0
+        iconPositionY: 0,
+        themeFixed: false
     },
     buttonmatrix: {
         w: 240,
@@ -563,6 +577,7 @@ export const WIDGET_DEFAULTS = {
         iconSize: 1,
         iconGap: 0,
         iconPositionX: 0,
-        iconPositionY: 0
+        iconPositionY: 0,
+        themeFixed: false
     }
 };

web-interface/src/stores/editor.js

@@ -19,6 +19,7 @@ export const useEditorStore = defineStore('editor', () => {
     const showGrid = ref(true);
     const snapToGrid = ref(true);
     const gridSize = ref(20);
+    const nightPreview = ref(false);
     const powerLinkMode = reactive({ active: false, powerflowId: null, fromNodeId: null });
 
     const nextScreenId = ref(0);
@@ -273,6 +274,7 @@ export const useEditorStore = defineStore('editor', () => {
             name: `Screen ${id}`,
             mode: 0,
             bgColor: '#1A1A2E',
+            nightBgColor: '#0E1217',
             bgImage: '',
             bgImageMode: 1,
             widgets: []
@@ -406,7 +408,8 @@ export const useEditorStore = defineStore('editor', () => {
             iconSize: defaults.iconSize || 1,
             iconGap: defaults.iconGap || 8,
             iconPositionX: defaults.iconPositionX || 8,
-            iconPositionY: defaults.iconPositionY || 8
+            iconPositionY: defaults.iconPositionY || 8,
+            themeFixed: defaults.themeFixed ?? false
         };
 
         if (defaults.conditions !== undefined) {
@@ -656,6 +659,7 @@ export const useEditorStore = defineStore('editor', () => {
         knxAddresses,
         selectedWidgetId,
         activeScreenId,
+        nightPreview,
         canvasScale,
         showGrid,
         snapToGrid,

web-interface/src/utils.js

@@ -4,6 +4,44 @@ export function typeKeyFor(type) {
     return TYPE_KEYS[type] || 'label';
 }
 
+export function invertLightness(hex) {
+    const r = parseInt(hex.slice(1, 3), 16) / 255;
+    const g = parseInt(hex.slice(3, 5), 16) / 255;
+    const b = parseInt(hex.slice(5, 7), 16) / 255;
+    const maxC = Math.max(r, g, b);
+    const minC = Math.min(r, g, b);
+    const delta = maxC - minC;
+    let L = (maxC + minC) * 0.5;
+    let S = 0, H = 0;
+    if (delta > 0.0001) {
+        S = L < 0.5 ? delta / (maxC + minC) : delta / (2 - maxC - minC);
+        if (maxC === r)      H = ((g - b) / delta + (g < b ? 6 : 0)) / 6;
+        else if (maxC === g) H = ((b - r) / delta + 2) / 6;
+        else                 H = ((r - g) / delta + 4) / 6;
+    }
+    L = 1 - L;
+    const hue2rgb = (p, q, t) => {
+        if (t < 0) t += 1;
+        if (t > 1) t -= 1;
+        if (t < 1/6) return p + (q - p) * 6 * t;
+        if (t < 1/2) return q;
+        if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;
+        return p;
+    };
+    let ro, go, bo;
+    if (S < 0.0001) {
+        ro = go = bo = L;
+    } else {
+        const q = L < 0.5 ? L * (1 + S) : L + S - L * S;
+        const p = 2 * L - q;
+        ro = hue2rgb(p, q, H + 1/3);
+        go = hue2rgb(p, q, H);
+        bo = hue2rgb(p, q, H - 1/3);
+    }
+    const toHex = v => Math.round(Math.max(0, Math.min(1, v)) * 255).toString(16).padStart(2, '0');
+    return `#${toHex(ro)}${toHex(go)}${toHex(bo)}`;
+}
+
 export function clamp(value, min, max) {
     if (Number.isNaN(value)) return min;
     return Math.max(min, Math.min(max, value));
@@ -171,6 +209,7 @@ export function normalizeScreen(screen, nextScreenIdRef, nextWidgetIdRef) {
     if (!screen.name) screen.name = `Screen ${screen.id}`;
     if (screen.mode === undefined || screen.mode === null) screen.mode = 0;
     if (!screen.bgColor) screen.bgColor = '#1A1A2E';
+    if (!screen.nightBgColor) screen.nightBgColor = '#0E1217';
     if (screen.bgImage === undefined) screen.bgImage = '';
     if (screen.bgImageMode === undefined) screen.bgImageMode = 1;
     if (!Array.isArray(screen.widgets)) screen.widgets = [];