chore: inline online fonts with base64

.gitignore

@@ -20,3 +20,5 @@ data.json
 
 # Exclude macOS Finder (System Explorer) View States
 .DS_Store
+
+tmp/

extract_katexcss.py

@@ -0,0 +1,36 @@
+import re
+import urllib.request
+import base64
+import os
+
+# define a function to encode a file as base64
+def encode_file_as_base64(filename):
+    print("processing: ", filename)
+    url_base = "https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.11.1/fonts/"
+    url = url_base + filename
+
+    if not os.path.isfile("tmp/" + filename):
+        urllib.request.urlretrieve(url, "tmp/" + filename)
+
+    with open("tmp/" + filename, 'rb') as f:
+        return base64.b64encode(f.read()).decode("utf-8")
+
+# read the CSS file into a string
+with open('katex.min.css', 'r') as f:
+    css_string = f.read()
+
+# define the regular expression pattern
+pattern = r'url\((.*?)\) format\((.*?)\)'
+
+# define a function to replace the matched pattern with the base64-encoded data URI
+def replace_match(match):
+    url = match.group(1)
+    filename = url[6:]
+
+    format = match.group(2)
+    base64_code = encode_file_as_base64(filename)
+    return f'url(data:application/{filename};charset=utf-8;base64,{base64_code}) format({format})'
+
+new_css_string = re.sub(pattern, replace_match, css_string)
+with open('new_styles.css', 'w') as f:
+    f.write(new_css_string)