diff --git a/CrossDown/Core.py b/CrossDown/Core.py
index 2900717..9fea80d 100644
--- a/CrossDown/Core.py
+++ b/CrossDown/Core.py
@@ -24,6 +24,7 @@ class HighlightHtmlFormatter(HtmlFormatter):
     """
     用于给code highlight扩展添加语言类型
     """
+
     def __init__(self, lang_str='', **options):
         """
         初始化
@@ -209,6 +210,7 @@ class CodeLine(Treeprocessor):
     """
     渲染单行代码
     """
+
     def __init__(self, variable: Dict):
         super().__init__()
         self.variable = variable
@@ -334,6 +336,8 @@ class Code(Extension):
         # md.treeprocessors.register(CodeBlock(), 'code_block', 1)  # 渲染多行代码块
 
 
-def main(text: str, variable: Dict) -> Tuple[str, Dict[str, List[str]]]:
+def main(text: str, variable: Union[Dict[str, str], None] = None) -> Tuple[str, Dict[str, List[str]]]:
+    if variable is None:
+        variable = {}
     md = Markdown(extensions=[Basic(), Box(), Anchor()] + list(Extensions.values()) + [Code(variable=variable)])
     return md.convert(text), md.Meta
diff --git a/Static/styles.css b/Static/styles.css
index c4b2fd9..7687fb9 100644
--- a/Static/styles.css
+++ b/Static/styles.css
@@ -73,3 +73,5 @@ span.linenos.special { color: #000000; background-color: #ffffc0; padding-left:
 .codehilite .vi { color: #19177C } /* Name.Variable.Instance */
 .codehilite .vm { color: #19177C } /* Name.Variable.Magic */
 .codehilite .il { color: #666666 } /* Literal.Number.Integer.Long */
+
+.block {background-color: grey; color: white;} /* 灰色背景,白色文字 */
diff --git a/setup.py b/setup.py
index ce4b9ba..a0a134c 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@ with open("README.md", "r") as fh:
 
 setuptools.setup(
     name="CrossDown",
-    version="2.0.0",
+    version="2.0.1",
     author="CrossDark",
     author_email="liuhanbo333@icloud.com",
     description="CrossDark's MarkDown",