diff --git a/libbalsa/misc.c b/libbalsa/misc.c
index d892a28..50c38d5 100644
--- a/libbalsa/misc.c
+++ b/libbalsa/misc.c
@@ -1369,7 +1369,8 @@ libbalsa_size_to_gchar(guint64 size)
 
 gchar *
 libbalsa_font_string_to_css(const gchar * font_string,
-                            const gchar * name)
+                            const gchar * name,
+                            GtkWidget   * window)
 {
     PangoFontDescription *desc;
     guint mask;
@@ -1377,6 +1378,7 @@ libbalsa_font_string_to_css(const gchar * font_string,
 
     g_return_val_if_fail(font_string != NULL, NULL);
     g_return_val_if_fail(name != NULL, NULL);
+    g_return_val_if_fail(window != NULL, NULL);
 
     desc = pango_font_description_from_string(font_string);
     mask = pango_font_description_get_set_fields(desc);
@@ -1454,12 +1456,17 @@ libbalsa_font_string_to_css(const gchar * font_string,
         gint size;
 
         size = pango_font_description_get_size(desc);
-        if (!pango_font_description_get_size_is_absolute(desc))
-            size *= gdk_screen_get_resolution(gdk_screen_get_default()) / 72;
+        if (!pango_font_description_get_size_is_absolute(desc)) {
+            g_message("size %d is not absolute", size);
+            size *= gdk_screen_get_resolution(gdk_window_get_screen(gtk_widget_get_window(window))) / 72;
+        } else {
+            g_message("size %d is absolute", size);
+        }
         size = PANGO_PIXELS(size);
         g_string_append_printf(string, "font-size: %dpx;\n", size);
     }
     g_string_append_c(string, '}');
+    g_message("CSS: \"%s\"", string->str);
 
     pango_font_description_free(desc);
 
diff --git a/libbalsa/misc.h b/libbalsa/misc.h
index fc4d6fb..ebb2853 100644
--- a/libbalsa/misc.h
+++ b/libbalsa/misc.h
@@ -167,6 +167,8 @@ gchar *libbalsa_size_to_gchar(guint64 length);
 
 gchar * libbalsa_text_to_html(const gchar * title, const gchar * body, const gchar * lang);
 GString * libbalsa_html_encode_hyperlinks(GString * paragraph);
-gchar *libbalsa_font_string_to_css(const gchar * font_string, const gchar * name);
+gchar *libbalsa_font_string_to_css(const gchar * font_string,
+                                   const gchar * name,
+                                   GtkWidget   * window);
 
 #endif				/* __LIBBALSA_MISC_H__ */
diff --git a/libbalsa/source-viewer.c b/libbalsa/source-viewer.c
index 208005f..eb89548 100644
--- a/libbalsa/source-viewer.c
+++ b/libbalsa/source-viewer.c
@@ -214,7 +214,8 @@ libbalsa_show_message_source(GtkApplication  * application,
     text = gtk_text_view_new();
 
     gtk_widget_set_name(text, BALSA_SOURCE_VIEWER);
-    css = libbalsa_font_string_to_css(font, BALSA_SOURCE_VIEWER);
+    window = gtk_application_window_new(application);
+    css = libbalsa_font_string_to_css(font, BALSA_SOURCE_VIEWER, window);
 
     css_provider = gtk_css_provider_new();
     gtk_css_provider_load_from_data(css_provider, css, -1, NULL);
@@ -234,7 +235,6 @@ libbalsa_show_message_source(GtkApplication  * application,
                                    GTK_POLICY_ALWAYS);
     gtk_container_add(GTK_CONTAINER(interior), GTK_WIDGET(text));
 
-    window = gtk_application_window_new(application);
     gtk_window_set_title(GTK_WINDOW(window), _("Message Source"));
     gtk_window_set_role(GTK_WINDOW(window), "message-source");
     gtk_window_set_default_size(GTK_WINDOW(window), *width, *height);
diff --git a/src/balsa-mime-widget-message.c b/src/balsa-mime-widget-message.c
index 003c9a5..b1c3da6 100644
--- a/src/balsa-mime-widget-message.c
+++ b/src/balsa-mime-widget-message.c
@@ -574,7 +574,8 @@ add_header_gchar(GtkGrid * grid, const gchar * header, const gchar * label,
         css = libbalsa_font_string_to_css(strcmp(header, "subject")
                                           ? balsa_app.message_font
                                           : balsa_app.subject_font,
-                                          BALSA_MESSAGE_HEADER);
+                                          BALSA_MESSAGE_HEADER,
+                                          GTK_WIDGET(balsa_app.main_window));
     }
 
     css_provider = gtk_css_provider_new();
diff --git a/src/balsa-mime-widget-text.c b/src/balsa-mime-widget-text.c
index 4e01557..2c56751 100644
--- a/src/balsa-mime-widget-text.c
+++ b/src/balsa-mime-widget-text.c
@@ -309,7 +309,8 @@ bm_modify_font_from_string(GtkWidget * widget, const char *font)
     GtkCssProvider *css_provider;
 
     gtk_widget_set_name(widget, BALSA_MESSAGE_TEXT_HEADER);
-    css = libbalsa_font_string_to_css(font, BALSA_MESSAGE_TEXT_HEADER);
+    css = libbalsa_font_string_to_css(font, BALSA_MESSAGE_TEXT_HEADER,
+                                      GTK_WIDGET(balsa_app.main_window));
 
     css_provider = gtk_css_provider_new();
     gtk_css_provider_load_from_data(css_provider, css, -1, NULL);
diff --git a/src/sendmsg-window.c b/src/sendmsg-window.c
index 3ea776f..b11fa61 100644
--- a/src/sendmsg-window.c
+++ b/src/sendmsg-window.c
@@ -2303,7 +2303,8 @@ create_email_or_string_entry(BalsaSendmsg * bsmsg,
 
         gtk_widget_set_name(arr[1], BALSA_COMPOSE_ENTRY);
         css = libbalsa_font_string_to_css(balsa_app.message_font,
-                                          BALSA_COMPOSE_ENTRY);
+                                          BALSA_COMPOSE_ENTRY,
+                                          GTK_WIDGET(balsa_app.main_window));
 
         css_provider = gtk_css_provider_new();
         gtk_css_provider_load_from_data(css_provider, css, -1, NULL);
@@ -2874,7 +2875,8 @@ create_text_area(BalsaSendmsg * bsmsg)
         GtkCssProvider *css_provider;
 
         css = libbalsa_font_string_to_css(balsa_app.message_font,
-                                          BALSA_COMPOSE_ENTRY);
+                                          BALSA_COMPOSE_ENTRY,
+                                          GTK_WIDGET(balsa_app.main_window));
 
         css_provider = gtk_css_provider_new();
         gtk_css_provider_load_from_data(css_provider, css, -1, NULL);