a.css

.item {
    padding: 0 18px;
    border-top: 1px solid #ccc;
}

.item:first-of-type {
    border-top: 0;
}

b.css

.item {
    padding: 0 18px;
}

.item:not(:first-of-type) {
    border-top: 1px solid #ccc;
}