diff --git a/src/calibre/gui2/book_details.py b/src/calibre/gui2/book_details.py
index 0ae2ecd580..c944a13d1e 100644
--- a/src/calibre/gui2/book_details.py
+++ b/src/calibre/gui2/book_details.py
@@ -75,6 +75,16 @@ def css(reset=False):
     return css.ans
 
 
+def resolve_colors(css):
+    app = QApplication.instance()
+    col = app.palette().color(QPalette.ColorRole.PlaceholderText).name() if app.is_dark_theme else '#666'
+    return css.replace('palette(placeholder-text)', col)
+
+
+def resolved_css():
+    return resolve_colors(css())
+
+
 def copy_all(text_browser):
     mf = getattr(text_browser, 'details', text_browser)
     c = QApplication.clipboard()
@@ -977,8 +987,7 @@ class BookInfo(HTMLDisplay):
         set_html(mi, html, self)
 
     def process_external_css(self, css):
-        col = self.palette().color(QPalette.ColorRole.PlaceholderText).name() if QApplication.instance().is_dark_theme else '#666'
-        return css.replace('palette(placeholder-text)', col)
+        return resolve_colors(css)
 
     def mouseDoubleClickEvent(self, ev):
         v = self.viewport()
diff --git a/src/calibre/gui2/comments_editor.py b/src/calibre/gui2/comments_editor.py
index 49a41b668e..a3988eb9be 100644
--- a/src/calibre/gui2/comments_editor.py
+++ b/src/calibre/gui2/comments_editor.py
@@ -24,7 +24,7 @@ from calibre.ebooks.chardet import xml_to_unicode
 from calibre.gui2 import (
     NO_URL_FORMATTING, choose_dir, choose_files, error_dialog, gprefs, is_dark_theme,
 )
-from calibre.gui2.book_details import css
+from calibre.gui2.book_details import resolved_css
 from calibre.gui2.flow_toolbar import create_flow_toolbar
 from calibre.gui2.widgets import LineEditECM
 from calibre.gui2.widgets2 import to_plain_text
@@ -288,7 +288,7 @@ class EditorWidget(QTextEdit, LineEditECM):  # {{{
     def __init__(self, parent=None):
         QTextEdit.__init__(self, parent)
         self.setTabChangesFocus(True)
-        self.document().setDefaultStyleSheet(css().replace('palette(placeholder-text)', 'gray') + '\n\nli { margin-top: 0.5ex; margin-bottom: 0.5ex; }')
+        self.document().setDefaultStyleSheet(resolved_css() + '\n\nli { margin-top: 0.5ex; margin-bottom: 0.5ex; }')
         font = self.font()
         f = QFontInfo(font)
         delta = tweaks['change_book_details_font_size_by'] + 1
diff --git a/src/calibre/gui2/markdown_editor.py b/src/calibre/gui2/markdown_editor.py
index 38fe135e95..3d101cd8b2 100644
--- a/src/calibre/gui2/markdown_editor.py
+++ b/src/calibre/gui2/markdown_editor.py
@@ -8,7 +8,7 @@ from qt.core import (
 )
 
 from calibre.gui2 import safe_open_url, gprefs
-from calibre.gui2.book_details import css
+from calibre.gui2.book_details import resolved_css
 from calibre.gui2.widgets2 import HTMLDisplay
 from calibre.library.comments import markdown as get_markdown
 
@@ -17,7 +17,7 @@ class Preview(HTMLDisplay):
 
     def __init__(self, parent=None):
         super().__init__(parent)
-        self.setDefaultStyleSheet(css().replace('palette(placeholder-text)', 'gray'))
+        self.setDefaultStyleSheet(resolved_css())
         self.setTabChangesFocus(True)
         self.base_url = None