diff --git a/serp.py b/serp.py
index c1603fd..9e40af0 100644
--- a/serp.py
+++ b/serp.py
@@ -3579,7 +3579,7 @@ ABOUT_CSS = """
 /* The Forge - TempleOS background */
 .chapter-forge {
     background: url('/static/vendor/templeos.png') center center repeat-y, #00FFFF;
-    background-size: auto;
+    background-size: 100%;
     position: relative;
 }
 .chapter-forge::before { content: none; }