diff --git a/files/assets/js/markdown.js b/files/assets/js/markdown.js
index b199de3aa..a395d9d08 100644
--- a/files/assets/js/markdown.js
+++ b/files/assets/js/markdown.js
@@ -4,11 +4,11 @@ marked.use({
 			name: 'mention',
 			level: 'inline',
 			start: function(src){
-				const match = src.match(/@[a-zA-Z0-9_\-]+/);
+				const match = src.match(/@[\w\-]{1,30}/);
 				return match != null ? match.index : -1;
 			},
 			tokenizer: function(src) {
-				const rule = /^@[a-zA-Z0-9_\-]+/;
+				const rule = /^@[\w\-]{1,30}/;
 				const match = rule.exec(src);
 				if (match){
 					return {
@@ -28,11 +28,11 @@ marked.use({
 			name: 'group_mention',
 			level: 'inline',
 			start: function(src){
-				const match = src.match(/![a-zA-Z0-9_\-]+/);
+				const match = src.match(/![\w\-]{3,25}/);
 				return match != null ? match.index : -1;
 			},
 			tokenizer: function(src) {
-				const rule = /^![a-zA-Z0-9_\-]+/;
+				const rule = /^![\w\-]{3,25}/;
 				const match = rule.exec(src);
 				if (match){
 					return {