diff --git a/src/misc.ts b/src/misc.ts
index 6450177..da886a4 100644
--- a/src/misc.ts
+++ b/src/misc.ts
@@ -177,7 +177,7 @@ export const applyRules = (data: string, rules: ApplyRule[]): string => {
 
 /** Removes trailing whitespace before the closing tag of block-level elements (`h1`–`h6`, `li`, `td`, `th`). */
 export const trimElementWhitespace = (str: string): string =>
-  str.replaceAll(/\s+(<\/(?:h[1-6]|li|td|th)>)/g, '$1')
+  str.replaceAll(/\s+(?=<\/(?:h[1-6]|li|td|th)>)/g, '')
 
 /**
  * Walks `tagRe` forward from `start`, tracking open/close depth, and returns the index