CSS fluid (unknown N) children (LESS)

fluid-children.less

.fluid {
    &:after {
        content: "";
        clear: both;
        display: block;
    }

    .item {
        float: left;
    }

    .item:first-child:nth-last-child(1) {
        width: 100%;
    }

    .item:first-child:nth-last-child(2),
    .item:first-child:nth-last-child(2) ~ .item {
        width: 50%;
    }

    .item:first-child:nth-last-child(3),
    .item:first-child:nth-last-child(3) ~ .item {
        width: 33.3333%;
    }

    .item:first-child:nth-last-child(4),
    .item:first-child:nth-last-child(4) ~ .item {
        width: 25%;
    }
}