diff --git a/build.py b/build.py
index b4ff6db..828599e 100644
--- a/build.py
+++ b/build.py
@@ -14,7 +14,15 @@ TEMPLATE = """<!DOCTYPE html>
     <script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.9/dist/katex.min.js"></script>
     <script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.9/dist/contrib/auto-render.min.js" onload="renderMathInElement(document.body);"></script>
     <style>
-        body {{ font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; max-width: 900px; margin: 0 auto; padding: 20px; line-height: 1.6; color: #333; }}
+        body {
+        background-image: url('/static/images/bg-math.svg');
+        background-repeat: repeat;
+        background-size: 800px 600px;
+        background-attachment: fixed;
+        { 
+            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; max-width: 900px; margin: 0 auto; padding: 20px; line-height: 1.6; color: #333; 
+        }
+        }
         header {{ border-bottom: 2px solid #003366; padding-bottom: 10px; margin-bottom: 30px; }}
         h1 {{ color: #003366; }}
         h2 {{ color: #004080; border-bottom: 1px solid #eee; padding-bottom: 5px; margin-top: 30px; }}
