diff --git a/core-server/utils/escapecss.js b/core-server/utils/escapecss.js
new file mode 100644
index 0000000000..8a30c0746b
--- /dev/null
+++ b/core-server/utils/escapecss.js
@@ -0,0 +1,95 @@
+/*\
+title: $:/core-server/modules/utils/escapecss.js
+type: application/javascript
+module-type: utils-node
+
+Provides CSS.escape() functionality.
+
+\*/
+
+"use strict";
+
+exports.escapeCSS = (function() {
+	// see also https://drafts.csswg.org/cssom/#serialize-an-identifier
+
+	/* eslint-disable */
+	/*! https://mths.be/cssescape v1.5.1 by @mathias | MIT license */
+	return function(value) {
+		if (arguments.length == 0) {
+			throw new TypeError('`CSS.escape` requires an argument.');
+		}
+		var string = String(value);
+		var length = string.length;
+		var index = -1;
+		var codeUnit;
+		var result = '';
+		var firstCodeUnit = string.charCodeAt(0);
+		while (++index < length) {
+			codeUnit = string.charCodeAt(index);
+			// Note: there’s no need to special-case astral symbols, surrogate
+			// pairs, or lone surrogates.
+
+			// If the character is NULL (U+0000), then the REPLACEMENT CHARACTER
+			// (U+FFFD).
+			if (codeUnit == 0x0000) {
+				result += '\uFFFD';
+				continue;
+			}
+
+			if (
+				// If the character is in the range [\1-\1F] (U+0001 to U+001F) or is
+				// U+007F, […]
+				(codeUnit >= 0x0001 && codeUnit <= 0x001F) || codeUnit == 0x007F ||
+				// If the character is the first character and is in the range [0-9]
+				// (U+0030 to U+0039), […]
+				(index == 0 && codeUnit >= 0x0030 && codeUnit <= 0x0039) ||
+				// If the character is the second character and is in the range [0-9]
+				// (U+0030 to U+0039) and the first character is a `-` (U+002D), […]
+				(
+					index == 1 &&
+					codeUnit >= 0x0030 && codeUnit <= 0x0039 &&
+					firstCodeUnit == 0x002D
+				)
+			) {
+				// https://drafts.csswg.org/cssom/#escape-a-character-as-code-point
+				result += '\\' + codeUnit.toString(16) + ' ';
+				continue;
+			}
+
+			if (
+				// If the character is the first character and is a `-` (U+002D), and
+				// there is no second character, […]
+				index == 0 &&
+				length == 1 &&
+				codeUnit == 0x002D
+			) {
+				result += '\\' + string.charAt(index);
+				continue;
+			}
+
+			// If the character is not handled by one of the above rules and is
+			// greater than or equal to U+0080, is `-` (U+002D) or `_` (U+005F), or
+			// is in one of the ranges [0-9] (U+0030 to U+0039), [A-Z] (U+0041 to
+			// U+005A), or [a-z] (U+0061 to U+007A), […]
+			if (
+				codeUnit >= 0x0080 ||
+				codeUnit == 0x002D ||
+				codeUnit == 0x005F ||
+				codeUnit >= 0x0030 && codeUnit <= 0x0039 ||
+				codeUnit >= 0x0041 && codeUnit <= 0x005A ||
+				codeUnit >= 0x0061 && codeUnit <= 0x007A
+			) {
+				// the character itself
+				result += string.charAt(index);
+				continue;
+			}
+
+			// Otherwise, the escaped character.
+			// https://drafts.csswg.org/cssom/#escape-a-character
+			result += '\\' + string.charAt(index);
+
+		}
+		return result;
+	};
+	/* eslint-enable */
+})();
diff --git a/core/modules/utils/escapecss.js b/core/modules/utils/escapecss.js
index f2248c4458..0df27da7b6 100644
--- a/core/modules/utils/escapecss.js
+++ b/core/modules/utils/escapecss.js
@@ -1,7 +1,7 @@
 /*\
 title: $:/core/modules/utils/escapecss.js
 type: application/javascript
-module-type: utils
+module-type: utils-browser
 
 Provides CSS.escape() functionality.
 
@@ -9,92 +9,6 @@ Provides CSS.escape() functionality.
 
 "use strict";
 
-// TODO -- resolve this construction
 exports.escapeCSS = (function() {
-	// use browser's native CSS.escape() function if available
-	if ($tw.browser && window.CSS && window.CSS.escape) {
-		return window.CSS.escape;
-	}
-
-	// otherwise, a utility method is provided
-	// see also https://drafts.csswg.org/cssom/#serialize-an-identifier
-
-	/*! https://mths.be/cssescape v1.5.1 by @mathias | MIT license */
-	return function(value) {
-		if (arguments.length == 0) {
-			throw new TypeError('`CSS.escape` requires an argument.');
-		}
-		var string = String(value);
-		var length = string.length;
-		var index = -1;
-		var codeUnit;
-		var result = '';
-		var firstCodeUnit = string.charCodeAt(0);
-		while (++index < length) {
-			codeUnit = string.charCodeAt(index);
-			// Note: there’s no need to special-case astral symbols, surrogate
-			// pairs, or lone surrogates.
-
-			// If the character is NULL (U+0000), then the REPLACEMENT CHARACTER
-			// (U+FFFD).
-			if (codeUnit == 0x0000) {
-				result += '\uFFFD';
-				continue;
-			}
-
-			if (
-				// If the character is in the range [\1-\1F] (U+0001 to U+001F) or is
-				// U+007F, […]
-				(codeUnit >= 0x0001 && codeUnit <= 0x001F) || codeUnit == 0x007F ||
-				// If the character is the first character and is in the range [0-9]
-				// (U+0030 to U+0039), […]
-				(index == 0 && codeUnit >= 0x0030 && codeUnit <= 0x0039) ||
-				// If the character is the second character and is in the range [0-9]
-				// (U+0030 to U+0039) and the first character is a `-` (U+002D), […]
-				(
-					index == 1 &&
-					codeUnit >= 0x0030 && codeUnit <= 0x0039 &&
-					firstCodeUnit == 0x002D
-				)
-			) {
-				// https://drafts.csswg.org/cssom/#escape-a-character-as-code-point
-				result += '\\' + codeUnit.toString(16) + ' ';
-				continue;
-			}
-
-			if (
-				// If the character is the first character and is a `-` (U+002D), and
-				// there is no second character, […]
-				index == 0 &&
-				length == 1 &&
-				codeUnit == 0x002D
-			) {
-				result += '\\' + string.charAt(index);
-				continue;
-			}
-
-			// If the character is not handled by one of the above rules and is
-			// greater than or equal to U+0080, is `-` (U+002D) or `_` (U+005F), or
-			// is in one of the ranges [0-9] (U+0030 to U+0039), [A-Z] (U+0041 to
-			// U+005A), or [a-z] (U+0061 to U+007A), […]
-			if (
-				codeUnit >= 0x0080 ||
-				codeUnit == 0x002D ||
-				codeUnit == 0x005F ||
-				codeUnit >= 0x0030 && codeUnit <= 0x0039 ||
-				codeUnit >= 0x0041 && codeUnit <= 0x005A ||
-				codeUnit >= 0x0061 && codeUnit <= 0x007A
-			) {
-				// the character itself
-				result += string.charAt(index);
-				continue;
-			}
-
-			// Otherwise, the escaped character.
-			// https://drafts.csswg.org/cssom/#escape-a-character
-			result += '\\' + string.charAt(index);
-
-		}
-		return result;
-	};
+	return window.CSS.escape;
 })();
diff --git a/editions/tw5.com/tiddlers/releasenotes/5.4.0/escapecss-split.tid b/editions/tw5.com/tiddlers/releasenotes/5.4.0/escapecss-split.tid
new file mode 100644
index 0000000000..7a9ee2b9d0
--- /dev/null
+++ b/editions/tw5.com/tiddlers/releasenotes/5.4.0/escapecss-split.tid
@@ -0,0 +1,10 @@
+title: $:/changenotes/5.4.0/#9475
+description: Split escapecss.js into two platforms
+release: 5.4.0
+tags: $:/tags/ChangeNote
+change-type: performance
+change-category: internal
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9475
+github-contributors: Leilei332
+
+Split [[$:/core/modules/utils/escapecss.js]] for two platforms: one for the browser, the other for Node.js. The `CSS.escape` polyfill is moved to `core-server`.
\ No newline at end of file