wrap color and number of homepage's articles

Hi Sami,
I’m trying to make a change on the wrap: I would like to change the color (or remove) of the border.
I’ve tried this on the child path:

#main .wrap {
    background:#FFFFFF;
    border: #FFFFFF;
}

This code affects the wrap just for the color inside but not for the border..

Tee other question regards the number of articles showed in the homepage: I would like to show just 4 articles instead of 7 (that is the default number).

Thank you,
Daniele
https://www.cronachemarziane.it