When using a dark color scheme fix the link color everywhere not just in the book details

src/calibre/gui2/__init__.py

@@ -16,7 +16,7 @@ from threading import Lock, RLock
 from PyQt5.Qt import (
     QT_VERSION, QApplication, QBuffer, QByteArray, QCoreApplication, QDateTime,
     QDesktopServices, QDialog, QEvent, QFileDialog, QFileIconProvider, QFileInfo,
-    QFont, QFontDatabase, QFontInfo, QFontMetrics, QIcon, QLocale,
+    QFont, QFontDatabase, QFontInfo, QFontMetrics, QIcon, QLocale, QColor,
     QNetworkProxyFactory, QObject, QSettings, QSocketNotifier, QStringListModel, Qt,
     QThread, QTimer, QTranslator, QUrl, pyqtSignal
 )
@@ -1011,6 +1011,11 @@ class Application(QApplication):
             prints('Using calibre Qt style:', self.using_calibre_style)
         if self.using_calibre_style:
             self.load_calibre_style()
+        self.is_dark_theme = is_dark_theme()
+        if self.is_dark_theme:
+            pal = self.palette()
+            pal.setColor(pal.Link, QColor('#6CB4EE'))
+            self.setPalette(pal)
 
     def load_calibre_style(self):
         icon_map = self.__icon_map_memory_ = {}

src/calibre/gui2/book_details.py

@@ -23,7 +23,7 @@ from calibre.ebooks.metadata.search_internet import (
 )
 from calibre.gui2 import (
     NO_URL_FORMATTING, choose_save_file, config, default_author_link, gprefs,
-    is_dark_theme, pixmap_to_data, rating_font, safe_open_url
+    pixmap_to_data, rating_font, safe_open_url
 )
 from calibre.gui2.dnd import (
     dnd_get_files, dnd_get_image, dnd_has_extension, dnd_has_image, image_extensions
@@ -61,13 +61,6 @@ def css(reset=False):
     return css.ans
 
 
-def themed_css(reset=False):
-    ans = css(reset)
-    if is_dark_theme():
-        ans = 'a { color: #6CB4EE }\n\n' + ans
-    return ans
-
-
 def copy_all(text_browser):
     mf = getattr(text_browser, 'details', text_browser)
     c = QApplication.clipboard()
@@ -562,10 +555,10 @@ class BookInfo(HTMLDisplay):
         ac.data = (None, None, None)
         ac.triggered.connect(self.remove_item_triggered)
         self.setFocusPolicy(Qt.NoFocus)
-        self.document().setDefaultStyleSheet(themed_css())
+        self.document().setDefaultStyleSheet(self.default_css + css())
 
     def refresh_css(self):
-        self.document().setDefaultStyleSheet(themed_css(True))
+        self.document().setDefaultStyleSheet(self.default_css + css(True))
 
     def remove_item_triggered(self):
         field, value, book_id = self.remove_item_action.data

src/calibre/gui2/dialogs/book_info.py

@@ -12,7 +12,7 @@ from PyQt5.Qt import (
 from calibre import fit_image
 from calibre.gui2 import NO_URL_FORMATTING, gprefs
 from calibre.gui2.book_details import (
-    themed_css, details_context_menu_event, render_html, set_html
+    css, details_context_menu_event, render_html, set_html
 )
 from calibre.gui2.ui import get_gui
 from calibre.gui2.widgets import CoverView
@@ -83,7 +83,7 @@ class Details(HTMLDisplay):
     def __init__(self, book_info, parent=None):
         HTMLDisplay.__init__(self, parent)
         self.book_info = book_info
-        self.document().setDefaultStyleSheet(themed_css())
+        self.document().setDefaultStyleSheet(self.default_css + css())
 
     def sizeHint(self):
         return QSize(350, 350)

src/calibre/gui2/widgets2.py

@@ -434,6 +434,13 @@ class HTMLDisplay(QTextBrowser):
 
     def __init__(self, parent=None):
         QTextBrowser.__init__(self, parent)
+        self.default_css = ''
+        app = QApplication.instance()
+        if app.is_dark_theme:
+            pal = app.palette()
+            col = pal.color(pal.Link)
+            self.default_css = 'a { color: %s }\n\n' % col.name(col.HexRgb)
+            self.document().setDefaultStyleSheet(self.default_css)
         font = self.font()
         f = QFontInfo(font)
         delta = tweaks['change_book_details_font_size_by'] + 1