diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index 22b36d438c..17fb801177 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -387,12 +387,19 @@ class Inspector(QWidget):
 
 
 def system_colors():
-    pal = QApplication.instance().palette()
-    return {
+    app = QApplication.instance()
+    is_dark_theme = app.is_dark_theme
+    pal = app.palette()
+    ans = {
         'background': pal.color(pal.Base).name(),
         'foreground': pal.color(pal.Text).name(),
-        'link': pal.color(pal.Link).name(),
     }
+    if is_dark_theme:
+        # only override link colors for dark themes
+        # since if the book specifies its own link colors
+        # they will likely work well with light themes
+        ans['link'] = pal.color(pal.Link).name()
+    return ans
 
 
 class WebView(RestartingWebEngineView):
diff --git a/src/pyj/read_book/globals.pyj b/src/pyj/read_book/globals.pyj
index b906c67f31..8244679b77 100644
--- a/src/pyj/read_book/globals.pyj
+++ b/src/pyj/read_book/globals.pyj
@@ -60,7 +60,9 @@ def set_system_colors(spec):
     c = default_color_schemes.system
     c.foreground = spec.foreground
     c.background = spec.background
-    c.link = spec.link
+    v'delete c.link'
+    if spec.link:
+        c.link = spec.link
 
 register_callback(def():
     # Ensure the color scheme names are translated