finish

Wulian233 · Wulian233 · commit e2d73322632d · 2025-10-11T20:55:55.000+08:00
diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst
@@ -297,9 +297,9 @@ Improved modules
 calendar
 --------
 
-* The calendar pages generated by the :class:`calendar.HTMLCalendar` class now
-  use the HTML5 standard.
-  (Contributed by Jiahao Li in :gh:`137634`.)
+* Calendar pages generated by the :class:`calendar.HTMLCalendar` class now support
+  dark mode and have been migrated to the HTML5 standard for improved accessibility.
+  (Contributed by Jiahao Li and Hugo van Kemenade in :gh:`137634`.)
 
 
 collections
@@ -329,7 +329,6 @@ collections.abc
   previously emitted if it was merely imported or accessed from the
   :mod:`!collections.abc` module.
 
-
 dbm
 ---
 
diff --git a/Lib/calendar.py b/Lib/calendar.py
@@ -588,6 +588,11 @@ def formatyearpage(self, theyear, width=3, css='calendar.css', encoding=None):
         a(f'<meta charset="{encoding}">\n')
         a('<meta name="viewport" content="width=device-width, initial-scale=1">\n')
         a(f'<title>Calendar for {theyear}</title>\n')
+        a('<style>\n')
+        a(':root { color-scheme: light dark; }\n')
+        a('table.year { border: solid; }\n')
+        a('table.year > tbody > tr > td { border: solid; vertical-align: top; }\n')
+        a('</style>\n')
         if css is not None:
             a(f'<link rel="stylesheet" href="{css}">\n')
         a('</head>\n')
diff --git a/Lib/test/test_calendar.py b/Lib/test/test_calendar.py
@@ -113,13 +113,20 @@
 
 default_format = dict(year="year", month="month", encoding="ascii")
 
+result_2004_css = """<style>
+:root { color-scheme: light dark; }
+table.year { border: solid; }
+table.year > tbody > tr > td { border: solid; vertical-align: top; }
+</style>"""
+
 result_2004_html = """\
 <!DOCTYPE html>
 <html lang="en">
 <head>
 <meta charset="{encoding}">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <title>Calendar for 2004</title>
+{css_styles}
 <link rel="stylesheet" href="calendar.css">
 </head>
 <body>
@@ -385,10 +392,12 @@ def check_htmlcalendar_encoding(self, req, res):
         cal = calendar.HTMLCalendar()
         format_ = default_format.copy()
         format_["encoding"] = req or 'utf-8'
+        format_with_css = {**format_, "css_styles": result_2004_css}
+        formatted_html = result_2004_html.format(**format_with_css)
         output = cal.formatyearpage(2004, encoding=req)
         self.assertEqual(
             output,
-            result_2004_html.format(**format_).encode(res)
+            formatted_html.encode(res)
         )
 
     def test_output(self):
@@ -1196,7 +1205,9 @@ def test_html_output_current_year(self):
     def test_html_output_year_encoding(self):
         for run in self.runners:
             output = run('-t', 'html', '--encoding', 'ascii', '2004')
-            self.assertEqual(output, result_2004_html.format(**default_format).encode('ascii'))
+            format_with_css = default_format.copy()
+            format_with_css["css_styles"] = result_2004_css
+            self.assertEqual(output, result_2004_html.format(**format_with_css).encode('ascii'))
 
     def test_html_output_year_css(self):
         self.assertFailure('-t', 'html', '-c')
diff --git a/Misc/NEWS.d/next/Library/2025-08-11-14-18-32.gh-issue-137634.M7iBG6.rst b/Misc/NEWS.d/next/Library/2025-08-11-14-18-32.gh-issue-137634.M7iBG6.rst
@@ -1,2 +1,2 @@
-The calendar pages generated by the :class:`calendar.HTMLCalendar` class now
-use the HTML5 standard.
+Calendar pages generated by the :class:`calendar.HTMLCalendar` class now support
+dark mode and have been migrated to the HTML5 standard for improved accessibility.
