diff --git a/reader/browser/BrowserPage.cpp b/reader/browser/BrowserPage.cpp
index 22d1cc361..3ab427dad 100644
--- a/reader/browser/BrowserPage.cpp
+++ b/reader/browser/BrowserPage.cpp
@@ -1289,12 +1289,9 @@ QPixmap BrowserPage::applyNightMode(const QPixmap &src)
     if (img.isNull())
         return src;
 
-    // 统一为 ARGB32 便于逐行扫描
-    if (img.format() != QImage::Format_ARGB32 &&
-        img.format() != QImage::Format_ARGB32_Premultiplied &&
-        img.format() != QImage::Format_RGB32) {
+    // 统一转非预乘 ARGB32，避免对 ARGB32_Premultiplied 写入非预乘值导致半透明像素错误
+    if (img.format() != QImage::Format_ARGB32)
         img = img.convertToFormat(QImage::Format_ARGB32);
-    }
 
     const int w = img.width();
     const int h = img.height();
@@ -1306,11 +1303,17 @@ QPixmap BrowserPage::applyNightMode(const QPixmap &src)
             const int alpha = qAlpha(px);
 
             // HSL 亮度反转：保留色相(H)和饱和度(S)，仅反转亮度(L)
-            // 白(255) → 黑(0)，黑(0) → 白(255)，彩色仅变暗、色相不偏移
+            // 白(255) → 黑，黑(0) → 白(255)，彩色仅变暗、色相不偏移
+            // 两端收敛：下限钳制 30(#1E1E1E)，反转后 ≥192 提亮纯白（原图 L≤63 深色文字）
+            const int kMinLightAfterInvert = 30;       // #1E1E1E 的 HSL 亮度值
+            const int kMaxLightBoostThreshold = 192;   // 0xC0，提亮阈值
             QColor c = QColor::fromRgb(qRed(px), qGreen(px), qBlue(px));
             int hue, sat, light, dummy;
             c.getHsl(&hue, &sat, &light, &dummy);
             light = 255 - light;
+            if (light >= kMaxLightBoostThreshold)
+                light = 255;
+            light = qMax(light, kMinLightAfterInvert);
             c.setHsl(hue, sat, light);
             line[x] = qRgba(c.red(), c.green(), c.blue(), alpha);
         }
diff --git a/reader/sidebar/BookMarkDelegate.cpp b/reader/sidebar/BookMarkDelegate.cpp
index 0aa84e8b9..de692eed4 100644
--- a/reader/sidebar/BookMarkDelegate.cpp
+++ b/reader/sidebar/BookMarkDelegate.cpp
@@ -1,5 +1,5 @@
-// Copyright (C) 2019 ~ 2020 Uniontech Software Technology Co.,Ltd.
-// SPDX-FileCopyrightText: 2023 UnionTech Software Technology Co., Ltd.
+// Copyright (C) 2019 ~ 2026 Uniontech Software Technology Co.,Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -14,6 +14,7 @@
 #include <QItemSelectionModel>
 #include <QAbstractItemView>
 #include <QPainterPath>
+#include <QImage>
 
 BookMarkDelegate::BookMarkDelegate(QAbstractItemView *parent)
     : DStyledItemDelegate(parent)
@@ -21,6 +22,7 @@ BookMarkDelegate::BookMarkDelegate(QAbstractItemView *parent)
     qCInfo(appLog) << "Creating BookMarkDelegate with parent widget:" << parent;
 
     m_parent = parent;
+    m_darkPixmapCache.setMaxCost(8 * 1024 * 1024); // 反色缓存预算 8MB，按像素字节数计费
 }
 
 void BookMarkDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
@@ -45,7 +47,51 @@ void BookMarkDelegate::paint(QPainter *painter, const QStyleOptionViewItem &opti
             QPainterPath clipPath;
             clipPath.addRoundedRect(rect, borderRadius, borderRadius);
             painter->setClipPath(clipPath);
-            painter->drawPixmap(rect.x(), rect.y(), scalePix);
+            // 深色主题下将白底缩略图反色为黑底白字（仅绘制时反色，不改缓存原图）：
+            // HSL 亮度反转，下限钳制 37(#252525)，反转后 ≥192 提亮纯白。
+            if (DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->themeType() == DTK_NAMESPACE::Gui::DGuiApplicationHelper::DarkType) {
+                // 按源图 cacheKey() 缓存反色结果，避免每次重绘重复逐像素计算
+                QPixmap invertedPixmap;
+                if (QPixmap *cached = m_darkPixmapCache.object(pixmap.cacheKey())) {
+                    invertedPixmap = *cached;
+                } else {
+                    QImage img = scalePix.toImage();
+                    if (!img.isNull()) {
+                        if (img.format() != QImage::Format_ARGB32)
+                            img = img.convertToFormat(QImage::Format_ARGB32);
+                        const int w = img.width();
+                        const int h = img.height();
+                        const int kMinLightAfterInvert = 37;       // #252525
+                        const int kMaxLightBoostThreshold = 192;   // 0xC0，提亮阈值
+                        for (int y = 0; y < h; ++y) {
+                            QRgb *line = reinterpret_cast<QRgb *>(img.scanLine(y));
+                            for (int x = 0; x < w; ++x) {
+                                const QRgb px = line[x];
+                                const int alpha = qAlpha(px);
+                                QColor c = QColor::fromRgb(qRed(px), qGreen(px), qBlue(px));
+                                int hue, sat, light, dummy;
+                                c.getHsl(&hue, &sat, &light, &dummy);
+                                light = 255 - light;
+                                if (light >= kMaxLightBoostThreshold)
+                                    light = 255;
+                                light = qMax(light, kMinLightAfterInvert);
+                                c.setHsl(hue, sat, light);
+                                line[x] = qRgba(c.red(), c.green(), c.blue(), alpha);
+                            }
+                        }
+                        invertedPixmap = QPixmap::fromImage(img);
+                        invertedPixmap.setDevicePixelRatio(scalePix.devicePixelRatio());
+                        m_darkPixmapCache.insert(pixmap.cacheKey(), new QPixmap(invertedPixmap),
+                                                 img.width() * img.height() * 4); // ARGB32 每像素固定 4 字节
+                    }
+                }
+                if (!invertedPixmap.isNull())
+                    painter->drawPixmap(rect.x(), rect.y(), invertedPixmap);
+                else
+                    painter->drawPixmap(rect.x(), rect.y(), scalePix);
+            } else {
+                painter->drawPixmap(rect.x(), rect.y(), scalePix);
+            }
             painter->restore();
         }
 
@@ -59,7 +105,13 @@ void BookMarkDelegate::paint(QPainter *painter, const QStyleOptionViewItem &opti
             painter->setPen(QPen(DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().highlight().color(), 2));
             painter->drawRoundedRect(rect, borderRadius, borderRadius);
         } else {
-            painter->setPen(QPen(DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().frameShadowBorder().color(), 1));
+            // 未选中：深色主题下 frameShadowBorder 与深色背景混色，改用 windowText@0.2α
+            QColor frameColor = DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().frameShadowBorder().color();
+            if (DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->themeType() == DTK_NAMESPACE::Gui::DGuiApplicationHelper::DarkType) {
+                frameColor = DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().windowText().color();
+                frameColor.setAlphaF(0.2);
+            }
+            painter->setPen(QPen(frameColor, 1));
             painter->drawRoundedRect(rect, borderRadius, borderRadius);
         }
         painter->restore();
diff --git a/reader/sidebar/BookMarkDelegate.h b/reader/sidebar/BookMarkDelegate.h
index 1bcb18a61..2aef507fa 100644
--- a/reader/sidebar/BookMarkDelegate.h
+++ b/reader/sidebar/BookMarkDelegate.h
@@ -1,5 +1,5 @@
-// Copyright (C) 2019 ~ 2020 Uniontech Software Technology Co.,Ltd.
-// SPDX-FileCopyrightText: 2023 UnionTech Software Technology Co., Ltd.
+// Copyright (C) 2019 ~ 2026 Uniontech Software Technology Co.,Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -8,6 +8,9 @@
 
 #include <DStyledItemDelegate>
 
+#include <QCache>
+#include <QPixmap>
+
 DWIDGET_USE_NAMESPACE
 
 /**
@@ -31,6 +34,11 @@ class BookMarkDelegate : public DStyledItemDelegate
 
 private:
     QAbstractItemView *m_parent = nullptr;
+
+    /**
+     * @brief 深色主题反色结果缓存（键：源图 cacheKey()；paint() 为 const 故 mutable）
+     */
+    mutable QCache<qint64, QPixmap> m_darkPixmapCache;
 };
 
 #endif // BOOKMARKDELEGATE_H
diff --git a/reader/sidebar/ThumbnailDelegate.cpp b/reader/sidebar/ThumbnailDelegate.cpp
index bdc9b794b..b4fccc9f7 100644
--- a/reader/sidebar/ThumbnailDelegate.cpp
+++ b/reader/sidebar/ThumbnailDelegate.cpp
@@ -68,6 +68,7 @@ void ThumbnailDelegate::paint(QPainter *painter, const QStyleOptionViewItem &opt
             // 不修改 DocSheet 中缓存的真实缩略图(始终为白底)，避免主题切换时双重反色。
             // 采用与 BrowserPage::applyNightMode 相同的 HSL 亮度反转算法：
             // 仅反转 Lightness 通道，保留 Hue/Saturation，避免图片色相偏移 180°。
+            // 两端收敛：下限钳制 37(#252525)，反转后 ≥192 提亮纯白
             //   白底黑字 → 黑底白字（文字/背景正确反色）
             //   彩色图片/链接 → 仅变暗，色相保持
             if (DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->themeType() == DTK_NAMESPACE::Gui::DGuiApplicationHelper::DarkType) {
@@ -77,6 +78,8 @@ void ThumbnailDelegate::paint(QPainter *painter, const QStyleOptionViewItem &opt
                         img = img.convertToFormat(QImage::Format_ARGB32);
                     const int w = img.width();
                     const int h = img.height();
+                    const int kMinLightAfterInvert = 37;       // #252525
+                    const int kMaxLightBoostThreshold = 192;   // 0xC0，提亮阈值
                     for (int y = 0; y < h; ++y) {
                         QRgb *line = reinterpret_cast<QRgb *>(img.scanLine(y));
                         for (int x = 0; x < w; ++x) {
@@ -86,6 +89,9 @@ void ThumbnailDelegate::paint(QPainter *painter, const QStyleOptionViewItem &opt
                             int hue, sat, light, dummy;
                             c.getHsl(&hue, &sat, &light, &dummy);
                             light = 255 - light;
+                            if (light >= kMaxLightBoostThreshold)
+                                light = 255;
+                            light = qMax(light, kMinLightAfterInvert);
                             c.setHsl(hue, sat, light);
                             line[x] = qRgba(c.red(), c.green(), c.blue(), alpha);
                         }
@@ -110,7 +116,13 @@ void ThumbnailDelegate::paint(QPainter *painter, const QStyleOptionViewItem &opt
             painter->setPen(QPen(DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().highlight().color(), 2));
             painter->drawRoundedRect(rect, borderRadius, borderRadius);
         } else {
-            painter->setPen(QPen(DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().frameShadowBorder().color(), 1));
+            // 未选中：深色主题下 frameShadowBorder 与深色背景混色，改用 windowText@0.2α
+            QColor frameColor = DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().frameShadowBorder().color();
+            if (DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->themeType() == DTK_NAMESPACE::Gui::DGuiApplicationHelper::DarkType) {
+                frameColor = DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().windowText().color();
+                frameColor.setAlphaF(0.2);
+            }
+            painter->setPen(QPen(frameColor, 1));
             painter->drawRoundedRect(rect, borderRadius, borderRadius);
             painter->setPen(QPen(DTK_NAMESPACE::Gui::DGuiApplicationHelper::instance()->applicationPalette().windowText().color()));
         }