reduced max size of css variable to 512KB

Former-commit-id: 6b9b86770c4eb3177b894094f83b2d6c6e2cc1ba

lib/single-file/single-file-core.js

@@ -1398,7 +1398,7 @@ this.singlefile.lib.core = this.singlefile.lib.core || (() => {
 	const EMPTY_DATA_URI = "data:null;base64,";
 	const REGEXP_URL_HASH = /(#.+?)$/;
 	const SINGLE_FILE_VARIABLE_NAME_PREFIX = "--sf-img-";
-	const VAR_MAX_SIZE = 1024 * 1024 * 2;
+	const VAR_MAX_SIZE = 512 * 1024;
 
 	class ProcessorHelper {
 		static async evalTemplate(template = "", options, content, dontReplaceSlash) {