Backport PR #17667: Don't linewrap css in svg header.

timhoffm · meeseeksmachine · commit 4611bff05897 · 2020-06-18T16:46:20.000Z
diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -430,9 +430,7 @@ def _write_default_style(self):
             'stroke-linejoin': 'round',
             'stroke-linecap': 'butt'})
         writer.start('defs')
-        writer.start('style', type='text/css')
-        writer.data('*{%s}\n' % default_style)
-        writer.end('style')
+        writer.element('style', type='text/css', text='*{%s}' % default_style)
         writer.end('defs')
 
     def _make_id(self, type, content):
