How to change the Background of the quick reply

Hey!=)

I had a question about the background of the quick reply.
i saw a forum with this
https://2img.net/h/oi30.tinypic.com/245ihy9.png
and the ours is this
https://2img.net/h/oi31.tinypic.com/2m67ls6.png
How can i edit that, just like that?
The ours is dull and simple and we want like that border and background but we don't know the code for it
Can someone help us (me)?
Thank you in advance!=D

(i've posted this thread too in the other problems)

Hello, Sungmin, you only need to post a topic Once.

Kinko wrote:Hello, Sungmin, you only need to post a topic Once.

I know but i don't know exactly where...i don't get any help=S

Please avoid opening up multiple topics.

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