From 7fd61607cd28ec466717c78adfb1eb5b63add1f0 Mon Sep 17 00:00:00 2001
From: Wulian233 <1055917385@qq.com>
Date: Fri, 14 Mar 2025 18:45:33 +0800
Subject: [PATCH] gh-131204: Fix `difflib.HtmlDiff` may not use monospaced font
 (#131221)

Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
---
 Lib/difflib.py                                                  | 2 +-
 Lib/test/test_difflib_expect.html                               | 2 +-
 .../next/Library/2025-03-14-09-28-13.gh-issue-131204.wogNEX.rst | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2025-03-14-09-28-13.gh-issue-131204.wogNEX.rst

diff --git a/Lib/difflib.py b/Lib/difflib.py
index bc09aa128aa..4bba9e7ea5c 100644
--- a/Lib/difflib.py
+++ b/Lib/difflib.py
@@ -1633,7 +1633,7 @@ _file_template = """
 
 _styles = """
         :root {color-scheme: light dark}
-        table.diff {font-family:Courier; border:medium;}
+        table.diff {font-family: Menlo, Consolas, Monaco, Liberation Mono, Lucida Console, monospace; border:medium}
         .diff_header {background-color:#e0e0e0}
         td.diff_header {text-align:right}
         .diff_next {background-color:#c0c0c0}
diff --git a/Lib/test/test_difflib_expect.html b/Lib/test/test_difflib_expect.html
index 6c2ee49837e..9f33a9e9c9c 100644
--- a/Lib/test/test_difflib_expect.html
+++ b/Lib/test/test_difflib_expect.html
@@ -10,7 +10,7 @@
     <title></title>
     <style type="text/css">
         :root {color-scheme: light dark}
-        table.diff {font-family:Courier; border:medium;}
+        table.diff {font-family: Menlo, Consolas, Monaco, Liberation Mono, Lucida Console, monospace; border:medium}
         .diff_header {background-color:#e0e0e0}
         td.diff_header {text-align:right}
         .diff_next {background-color:#c0c0c0}
diff --git a/Misc/NEWS.d/next/Library/2025-03-14-09-28-13.gh-issue-131204.wogNEX.rst b/Misc/NEWS.d/next/Library/2025-03-14-09-28-13.gh-issue-131204.wogNEX.rst
new file mode 100644
index 00000000000..e821e61a0ca
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-03-14-09-28-13.gh-issue-131204.wogNEX.rst
@@ -0,0 +1 @@
+Use monospace font from System Font Stack for cross-platform support in  :class:`difflib.HtmlDiff`.