diff --git a/book/src/design/gadgets/sha256/table16.md b/book/src/design/gadgets/sha256/table16.md
index 65e9805..a99094f 100644
--- a/book/src/design/gadgets/sha256/table16.md
+++ b/book/src/design/gadgets/sha256/table16.md
@@ -791,7 +791,7 @@ Constraints:
 
 ### Compression region
 
-```
+```plaintext
 +----------------------------------------------------------+
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