fix .htaccess rule
diff --git a/.htaccess b/.htaccess
index fb5f8b3..c77a3bb 100644
--- a/.htaccess
+++ b/.htaccess
@@ -23,10 +23,8 @@
RewriteEngine On
RewriteCond "%{HTTP:Accept-Language}" "^zh" [NC]
-RewriteRule "^/$" "/zh/index.html"
-RewriteRule "^/index.html" "/zh/index.html" [L,R=301]
+RewriteRule "^/(index.html)?$" "/zh/index.html" [L,R=301]
RewriteCond "%{HTTP:Accept-Language}" "^en" [NC]
-RewriteRule "^/$" "/en/index.html"
-RewriteRule "^/index.html" "/en/index.html" [L,R=301]
+RewriteRule "^/(index.html)?$" "/en/index.html" [L,R=301]
