serving a conditional stylesheet for ie7

Hi.

first of all thanks for sharing this theme.

Here is my problem:

i'm developing a site and ie7 is "quite" required (probably the site will be visited also by people who ignore how to upgrade their browser).

i'm trying to develop a simpler version for ie7 (two colums and not responsive) but i have no luck at guessing how (and where to put) a conditional stylesheet statement. i tried with the usual wordpress function but seems not working.

Any suggestion?


Thanks, again