use two characters for the default avatar

customize.dist/src/less2/include/avatar.less

@@ -4,7 +4,7 @@
     @width: 30px
 ) {
     @avatar-width: @width;
-    @avatar-font-size: @width / 1.2;
+    @avatar-font-size: @width / 1.8;
 }
 .avatar_main(@width: 30px) {
     --LessLoader_require: LessLoader_currentFile();

customize.dist/src/less2/include/toolbar.less

@@ -855,7 +855,7 @@
                     span {
                         text-align: center;
                         width: 100%;
-                        font-size: 48px;
+                        font-size: 40px;
                         display: inline-flex;
                         justify-content: center;
                         align-items: center;

www/common/inner/common-mediatag.js

@@ -82,7 +82,16 @@ define([
     MT.displayAvatar = function (common, $container, href, name, _cb) {
         var cb = Util.once(Util.mkAsync(_cb || function () {}));
         var displayDefault = function () {
-            var text = Util.getFirstCharacter(name || Messages.anonymous);
+            name = (name || "").trim() || Messages.anonymous;
+            var parts = name.split(/\s+/);
+            var text;
+            if (parts.length > 1) {
+                text = parts.slice(0, 2).map(Util.getFirstCharacter).join('');
+            } else {
+                text = Util.getFirstCharacter(name);
+                text += Util.getFirstCharacter(name.replace(text, ''));
+            }
+
             var $avatar = $('<span>', {'class': 'cp-avatar-default'}).text(text);
             $container.append($avatar);
             if (cb) { cb(); }