[Client] Add [AppColors] application palette roles

The home-tab buttons' gradient over the static theme background was hardcoded, and accent-derived fallbacks could not be themed or edited: QPalette's role set is closed, so any application-specific color has to live in Cockatrice's own palette layer.

- Add an AppColor::Role enum (AccentStrong / AccentSoft) stored on PaletteConfig and round-tripped from palette-<scheme>.toml under a new [AppColors] section.
- Cache the applied app colors in ThemeManager and expose appColor(Role) with a palette-accent-derived fallback; emit paletteChanged() from applyStyleAndPalette so previews, scheme switches and OS dark mode repaint palette-driven widgets.
- Fill both app roles in PaletteGenerator::fromAccent and surface them as a dedicated section in the palette editor.
- Drive the home-tab buttons from appColor() whenever the background source is the theme (any theme, not just built-ins).
- Ship AccentStrong / AccentSoft values in the Fusion and Default default palettes so the static home-tab buttons keep their classic greens.

# Conflicts:
#	cockatrice/src/interface/widgets/general/home_widget.cpp

cockatrice/src/interface/palette_editor/palette_generator.cpp

@@ -150,6 +150,17 @@ PaletteConfig fromAccent(const QColor &accent, int intensity, const QString &sch
     cfg.colors[CG::Disabled][CR::HighlightedText] = disText;
     cfg.colors[CG::Inactive][CR::HighlightedText] = dark ? Qt::white : Qt::black;
 
+    // Accent: same primary hue as Highlight, so palettes derived from a
+    // QuickSetup accent always carry a matching Accent role.
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
+    set3(CR::Accent, hl, disText, hl);
+#endif
+
+    // Application role colors: Strong tracks the primary accent, while Soft is
+    // the lightened, desaturated companion used for button-gradient highlights.
+    cfg.appColors[AppColor::AccentStrong] = hl;
+    cfg.appColors[AppColor::AccentSoft] = hsl(accent.lightness() + 60, qRound(accent.hslSaturation() * 70 / 100.0));
+
     // BrightText
     QColor bright;
     if (achromatic) {

cockatrice/src/interface/palette_editor/palette_grid_widget.cpp

@@ -1,5 +1,7 @@
 #include "palette_grid_widget.h"
 
+#include "../theme_manager.h"
+
 #include <QApplication>
 #include <QGridLayout>
 #include <QLabel>
@@ -45,6 +47,11 @@ static const QMap<QPalette::ColorRole, const char *> ROLE_DESCRIPTIONS = {
     {QPalette::Shadow, QT_TR_NOOP("Very dark shadow colour")},
 };
 
+static const QMap<AppColor::Role, const char *> APP_ROLE_DESCRIPTIONS = {
+    {AppColor::AccentStrong, QT_TR_NOOP("Vivid primary accent (e.g. home-tab button gradient start)")},
+    {AppColor::AccentSoft, QT_TR_NOOP("Lighted, desaturated accent (e.g. home-tab button gradient end)")},
+};
+
 PaletteGridWidget::PaletteGridWidget(QWidget *parent) : QWidget(parent)
 {
     scroll = new QScrollArea(this);
@@ -122,6 +129,45 @@ void PaletteGridWidget::buildGrid(QWidget *host)
             grid->addWidget(btn, row + 1, col + 1, Qt::AlignHCenter | Qt::AlignVCenter);
         }
     }
+
+    // Application color section: one ColorButton per role below the role grid.
+    // These are not tied to a color group, so a single button spans the row.
+    QMetaEnum appEnum = QMetaEnum::fromType<AppColor::Role>();
+
+    const int appHeaderRow = roles.size() + 1;
+
+    auto *appHeader = new QLabel(tr("App colors"), host);
+    appHeader->setToolTip(tr("Application-specific colors layered on top of the Qt palette"));
+    QFont appHeaderFont = appHeader->font();
+    appHeaderFont.setBold(true);
+    appHeader->setFont(appHeaderFont);
+    appHeader->setAutoFillBackground(true);
+    appHeader->setContentsMargins(4, 4, 4, 4);
+    grid->addWidget(appHeader, appHeaderRow, 0, 1, 4);
+
+    for (int i = 0; i < appEnum.keyCount(); ++i) {
+        auto role = static_cast<AppColor::Role>(i);
+        const int row = appHeaderRow + 1 + i;
+
+        if (i % 2 == 0) {
+            for (int col = 0; col < 4; ++col) {
+                auto *shade = new QWidget(host);
+                shade->setAutoFillBackground(true);
+                grid->addWidget(shade, row, col);
+                rowShadeWidgets.push_back(shade);
+            }
+        }
+
+        auto *label = new QLabel(QString(appEnum.valueToKey(role)), host);
+        label->setToolTip(APP_ROLE_DESCRIPTIONS.value(role, {}));
+        label->setContentsMargins(4, 2, 8, 2);
+        grid->addWidget(label, row, 0);
+
+        auto *btn = new ColorButton(host);
+        connect(btn, &ColorButton::colorChanged, this, [this] { emit paletteChanged(); });
+        appColorButtons[role] = btn;
+        grid->addWidget(btn, row, 1, Qt::AlignHCenter | Qt::AlignVCenter);
+    }
 }
 
 void PaletteGridWidget::changeEvent(QEvent *e)
@@ -166,6 +212,16 @@ void PaletteGridWidget::loadPalette(const PaletteConfig &cfg)
             colorButtons[group][role]->setColor(color);
         }
     }
+
+    QMetaEnum appEnum = QMetaEnum::fromType<AppColor::Role>();
+    for (int i = 0; i < appEnum.keyCount(); ++i) {
+        auto role = static_cast<AppColor::Role>(i);
+        QColor color = cfg.appColors.value(role);
+        if (!color.isValid()) {
+            color = themeManager->appColor(role);
+        }
+        appColorButtons[role]->setColor(color);
+    }
 }
 
 PaletteConfig PaletteGridWidget::currentPaletteConfig() const
@@ -176,5 +232,12 @@ PaletteConfig PaletteGridWidget::currentPaletteConfig() const
             cfg.colors[group][role] = colorButtons[group][role]->getColor();
         }
     }
+
+    QMetaEnum appEnum = QMetaEnum::fromType<AppColor::Role>();
+    for (int i = 0; i < appEnum.keyCount(); ++i) {
+        auto role = static_cast<AppColor::Role>(i);
+        cfg.appColors[role] = appColorButtons[role]->getColor();
+    }
+
     return cfg;
 }

cockatrice/src/interface/palette_editor/palette_grid_widget.h

@@ -31,6 +31,7 @@ private:
     void refreshChromePalettes();
 
     QMap<QPalette::ColorGroup, QMap<QPalette::ColorRole, ColorButton *>> colorButtons;
+    QMap<AppColor::Role, ColorButton *> appColorButtons;
     QScrollArea *scroll;
     QWidget *gridHost;
     QVBoxLayout *layout;

cockatrice/src/interface/theme_config.cpp

@@ -133,6 +133,24 @@ QString PaletteConfig::toToml() const
         out += "\n";
     }
 
+    if (!appColors.isEmpty()) {
+        QMetaEnum appEnum = QMetaEnum::fromType<AppColor::Role>();
+
+        out += "[AppColors]\n";
+
+        for (auto it = appColors.cbegin(); it != appColors.cend(); ++it) {
+            const char *roleName = appEnum.valueToKey(it.key());
+
+            if (!roleName) {
+                continue;
+            }
+
+            out += QString("%1 = %2\n").arg(QString(roleName), -20).arg(it.value().name(QColor::HexArgb));
+        }
+
+        out += "\n";
+    }
+
     return out;
 }
 
@@ -152,6 +170,7 @@ PaletteConfig PaletteConfig::fromFile(const QString &filePath)
     }
 
     QMetaEnum roleEnum = QMetaEnum::fromType<QPalette::ColorRole>();
+    QMetaEnum appEnum = QMetaEnum::fromType<AppColor::Role>();
 
     QString currentSection;
     QPalette::ColorGroup currentGroup = QPalette::Active;
@@ -202,6 +221,26 @@ PaletteConfig PaletteConfig::fromFile(const QString &filePath)
             }
         }
 
+        QColor color(value);
+
+        if (!color.isValid()) {
+            continue;
+        }
+
+        if (currentSection.compare("AppColors", Qt::CaseInsensitive) == 0) {
+            if (key.startsWith("AppColor::")) {
+                key = key.mid(10);
+            }
+
+            int appRoleInt = appEnum.keyToValue(key.toUtf8().constData());
+
+            if (appRoleInt >= 0) {
+                cfg.appColors[static_cast<AppColor::Role>(appRoleInt)] = color;
+            }
+
+            continue;
+        }
+
         if (!currentSection.startsWith("Palette", Qt::CaseInsensitive)) {
             continue;
         }
@@ -216,11 +255,7 @@ PaletteConfig PaletteConfig::fromFile(const QString &filePath)
             continue;
         }
 
-        QColor color(value);
-
-        if (color.isValid()) {
-            cfg.colors[currentGroup][static_cast<QPalette::ColorRole>(roleInt)] = color;
-        }
+        cfg.colors[currentGroup][static_cast<QPalette::ColorRole>(roleInt)] = color;
     }
 
     return cfg;

cockatrice/src/interface/theme_config.h

@@ -3,9 +3,25 @@
 
 #include <QColor>
 #include <QMap>
+#include <QObject>
 #include <QPalette>
 #include <QString>
 
+// Application-specific color roles, layered on top of the fixed QPalette role
+// set. Stored in the same palette-<scheme>.toml under an [AppColors] section
+// and editable from the palette editor, so theme authors can control colors
+// beyond what Qt's palette can express.
+namespace AppColor
+{
+Q_NAMESPACE
+enum Role
+{
+    AccentStrong,
+    AccentSoft,
+};
+Q_ENUM_NS(Role)
+} // namespace AppColor
+
 struct ThemeConfig
 {
     QString colorScheme;
@@ -21,6 +37,7 @@ struct ThemeConfig
 struct PaletteConfig
 {
     QMap<QPalette::ColorGroup, QMap<QPalette::ColorRole, QColor>> colors;
+    QMap<AppColor::Role, QColor> appColors;
 
     bool hasPalette() const;
     QString toToml() const;

cockatrice/src/interface/theme_manager.cpp

@@ -416,6 +416,8 @@ void ThemeManager::applyStyleAndPalette(const QString &themeName,
     qApp->setPalette(base);
     qApp->setStyle(style);
 
+    currentAppColors = palCfg.appColors;
+
     // Force every widget to re-polish and repaint immediately rather than
     // waiting for natural expose events, which produces a patchwork of old
     // and new colours during a live preview.
@@ -428,6 +430,37 @@ void ThemeManager::applyStyleAndPalette(const QString &themeName,
         style->polish(widget);
         widget->update();
     }
+
+    emit paletteChanged();
+}
+
+QColor ThemeManager::appColor(AppColor::Role role) const
+{
+    const auto it = currentAppColors.constFind(role);
+    if (it != currentAppColors.constEnd()) {
+        return it.value();
+    }
+
+    // QPalette::Accent was introduced in Qt 6.6; before that the nearest
+    // accent is the selection highlight, which Accent defaults to when unset.
+    const QColor accent = qApp->palette().color(QPalette::Active,
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
+                                                QPalette::Accent);
+#else
+                                                QPalette::Highlight);
+#endif
+
+    if (role == AppColor::AccentSoft) {
+        constexpr int SOFT_SATURATION_PERCENT = 70;
+        constexpr int SOFT_LIGHTNESS_OFFSET = 60;
+
+        // Light end of the gradient: same hue, softened and lightened
+        return QColor::fromHsl(qMax(0, accent.hslHue()),
+                               qBound(0, qRound(accent.hslSaturation() * SOFT_SATURATION_PERCENT / 100.0), 255),
+                               qBound(0, accent.lightness() + SOFT_LIGHTNESS_OFFSET, 255));
+    }
+
+    return accent;
 }
 
 void ThemeManager::themeChangedSlot()

cockatrice/src/interface/theme_manager.h

@@ -50,6 +50,7 @@ private:
     QString currentThemePath;
     std::array<QBrush, Role::MaxRole + 1> brushes;
     QStringMap availableThemes;
+    QMap<AppColor::Role, QColor> currentAppColors;
     /*
       Internal cache for multiple backgrounds
     */
@@ -115,12 +116,17 @@ public:
     void reloadCurrentTheme();
     void previewPalette(const PaletteConfig &cfg, const QString &scheme);
 
+    // Resolves an application color role: the theme's stored [AppColors] value
+    // when present, otherwise a palette-accent-derived fallback.
+    QColor appColor(AppColor::Role role) const;
+
     QBrush &getBgBrush(Role zone);
     QBrush getExtraBgBrush(Role zone, int zoneId = 0);
 protected slots:
     void themeChangedSlot();
 signals:
     void themeChanged();
+    void paletteChanged();
 };
 
 extern ThemeManager *themeManager;

cockatrice/src/interface/widgets/general/home_widget.cpp

@@ -61,6 +61,7 @@ HomeWidget::HomeWidget(QWidget *parent, TabSupervisor *_tabSupervisor)
     // Scheme flips (light/dark/system with an OS switch) fire on themeManager,
     // not on SettingsCache::themeChanged, so re-resolve the variant background.
     connect(themeManager, &ThemeManager::themeChanged, this, &HomeWidget::initializeBackgroundFromSource);
+    connect(themeManager, &ThemeManager::paletteChanged, this, &HomeWidget::updateButtonsToBackgroundColor);
     connect(&SettingsCache::instance().appearance(), &AppearanceSettings::homeTabButtonColorChanged, this,
             &HomeWidget::updateButtonsToBackgroundColor);
 }
@@ -105,23 +106,27 @@ void HomeWidget::loadBackgroundSourceDeck()
     backgroundSourceDeck = deckOpt.has_value() ? deckOpt.value().deckList : DeckList();
 }
 
-static bool isDefaultBackgroundAndTheme()
+static bool usesThemeBackground()
 {
     QString sourceId = SettingsCache::instance().appearance().getHomeTabBackgroundSource();
-    return themeManager->isBuiltInTheme() && BackgroundSources::fromId(sourceId) == BackgroundSources::Theme;
+    return BackgroundSources::fromId(sourceId) == BackgroundSources::Theme;
+}
+
+static QPair<QColor, QColor> paletteDerivedButtonColors()
+{
+    return {themeManager->appColor(AppColor::AccentStrong), themeManager->appColor(AppColor::AccentSoft)};
 }
 
 QPair<QColor, QColor> HomeWidget::determineButtonColor() const
 {
-    static QPair defaultColor = {QColor::fromRgb(20, 140, 60), QColor::fromRgb(120, 200, 80)};
-
     auto colorSource =
         HomeTabButtonColor::intToSource(SettingsCache::instance().appearance().getHomeTabButtonColorSourceIndex());
 
     switch (colorSource) {
         case HomeTabButtonColor::Automatic: {
-            if (isDefaultBackgroundAndTheme()) {
-                return defaultColor;
+            if (usesThemeBackground()) {
+                // Static theme background: follow the theme's accent colors.
+                return paletteDerivedButtonColors();
             } else {
                 return extractDominantColors(background);
             }
@@ -130,7 +135,7 @@ QPair<QColor, QColor> HomeWidget::determineButtonColor() const
             return extractDominantColors(background);
     }
 
-    return defaultColor;
+    return paletteDerivedButtonColors();
 }
 
 void HomeWidget::setRandomCard(ExactCard &newCard)

cockatrice/themes/Default/palette-default-dark.toml

@@ -61,3 +61,7 @@ ToolTipBase          = #ffffffdc
 ToolTipText          = #ff000000
 PlaceholderText      = #6effffff
 
+
+[AppColors]
+AccentStrong        = #ff148c3c
+AccentSoft          = #ff78c850

cockatrice/themes/Fusion/palette-default-dark.toml

@@ -67,3 +67,7 @@ ToolTipText          = #ffd4d4d4
 PlaceholderText      = #80ffffff
 Accent               = #ff1e1e1e
 
+
+[AppColors]
+AccentStrong        = #ff148c3c
+AccentSoft          = #ff78c850

cockatrice/themes/Fusion/palette-default-light.toml

@@ -67,3 +67,7 @@ ToolTipText          = #ff000000
 PlaceholderText      = #80000000
 Accent               = #fff0f0f0
 
+
+[AppColors]
+AccentStrong        = #ff148c3c
+AccentSoft          = #ff78c850