Modify the logo on chat_landing page and link url

Content

I add a new widget to replace the standard widget RightNowLogo and I add the code to the chat_landing.php

 

In my base.css the code is as follows:

.rn_ALogo a {
    background:url(/euf/customer/assets/images/a.png) no-repeat scroll right 0 !important;
    display:block !important;
    height:29px !important;
    width:134px !important;
}

I have uploaded the picture to the directory

while the logo picture does not appear. What is the reason? Thanks.

it is my first question.

 

The second,

And I want to add a link when click the logo, it redirects to the link.

My controller.php includes follow code: