Hi!
Yes, that CSS looks correct to me.
To fix that problem, you will have to open the header file where you put the search shortcode in.
The faulty code should look something like:
[html]<div id="search-box">
<div id="search-box">
…. some code is probably in here….
</div>
</div>[/html]
and it should look something like:
[html]<div id="search-box">
…. some code is probably in here….
</div>[/html]