Some Fixes

src/__init__.py

@@ -5767,6 +5767,23 @@ def layout(self, rect=None, width=0, height=0, fontsize=11):
         self._reset_page_refs()
         self.init_doc()
 
+    def apply_css(self, css: str, append: bool = True):
+        """Apply CSS to a reflowable document.
+
+        If 'append' evaluates to True, the CSS will be appended to
+        the default CSS of this document type.
+        Otherwise the default CSS will be ignored.
+        """
+        if self.is_closed or self.is_encrypted:
+            raise ValueError("document closed or encrypted")
+        doc = self.this
+        if not mupdf.fz_is_document_reflowable(doc):
+            return
+        if not isinstance(css, str) or not css:
+            return
+        append = int(bool(append))  # ensure integer
+        mupdf.fz_style_document(doc, append, css)
+
     def load_page(self, page_id):
         """Load a page.
 

tests/test_markdown_support.py

@@ -40,3 +40,34 @@ def test_archive_links():
     assert links[0]["uri"] == "http://www.google.com"
     assert links[0]["kind"] == pymupdf.LINK_URI
     assert links[1]["kind"] == pymupdf.LINK_GOTO
+
+
+def test_markdown_style():
+    print()
+    if pymupdf.mupdf_version_tuple < (1, 28):
+        print('test_markdown_style(): not running because mupdf<1.28.')
+        return
+
+    font = pymupdf.Font("tiro")
+    arch = pymupdf.Archive(font.buffer, "tiro")
+
+    css = """@font-face {font-family: sans-serif; src: url(tiro);}"""
+    md = "Overriding sans-serif with Times-Roman."
+    for use_css in 0, 1:
+        md_doc = pymupdf.open(stream=md.encode(), filetype="md", archive=arch)
+        if use_css:
+            md_doc.apply_css(css)  # apply the CSS to the document
+
+        md_pdf_stream = md_doc.convert_to_pdf()
+        with pymupdf.open(stream=md_pdf_stream) as pdf_doc:
+            page = pdf_doc[0]
+            spans = [
+                s for b in page.get_text("dict")["blocks"] for l in b["lines"] for s in l["spans"]
+            ]
+
+        assert len(spans) == 1
+        print(f'test_markdown_style(): {use_css=} {spans[0]["font"]=}.')
+        if use_css:
+            assert "Roman" in spans[0]["font"]
+        else:
+            assert "Roman" not in spans[0]["font"]