Thanks Auge for your help so quickly!

Now the font of user name in the forum index page is normal!

I solved the problem according to your words.

I deleted the labels <strong> and </strong> from the file themes/default/subtemplates/index.inc.

Thanks the team of My Little Forum!!!

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I speak Chinese & Esperanto.
我说汉语和世界语。
Mi parolas ĉine kaj Esperante.
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http://reto.cn
my forum using MLF
http://reto.cn/forum