nit

build.py

@@ -135,6 +135,8 @@ title: {repr(input['title'])}
 def index_dir(dir):
     import frontmatter
     dir = Path(dir)
+    if dir.name.startswith('.'):
+        return
     if (dir / '.order').exists():
         order = (dir / '.order').read_text().split('\n')
         f = [p for p in dir.glob('*') if not p.name.startswith('.')]