Here is how to do it: paste the following in your edit CSS
.one_half {
width: 48%;
margin-right: 1%;
margin-left: 1%;
}
.one_third {
width: 32%;
margin-right: 1.3%;
}
.two_third {
width: 64%;
margin-right: 2.6%;
}
.one_fourth {
width: 24%;
margin-right: 1%;
}
.three_fourth {
width: 72%;
margin-right: 3%;
}
.one_fifth {
width: 19%;
margin-right: 1%;
}
.two_fifth {
width: 38%;
margin-right: 2%;
}
.three_fifth {
width: 57%;
margin-right: 3%;
}
.four_fifth {
width: 76%;
margin-right: 3%;
}
.one_sixth {
width: 16%;
margin-right: .6%;
}
You can change the % values accordingly.