CSS .-11u 。。。 .-7u .-6u .-5u 。。。什么意思

Question

我从网上下载了一个模板，在进行修改时发现了如下代码（在main.css文件中），最后几行的.-11u 等等我不明白是什么意思，求教大神讲解，多谢了！！

/* Grid */

.row {
    border-bottom: solid 1px transparent;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

.row > * {
    float: left;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

.row:after, .row:before {
    content: '';
    display: block;
    clear: both;
    height: 0;
}

.row.uniform > * > :first-child {
    margin-top: 0;
}

.row.uniform > * > :last-child {
    margin-bottom: 0;
}

.row.30 25 > * {
    padding: 0 0 0 0em;
}

.row.30 25 {
    margin: 0 0 -1px 0em;
}

.row.uniform.30 25 > * {
    padding: 0em 0 0 0em;
}

.row.uniform.30 25 {
    margin: 0em 0 -1px 0em;
}

.row > * {
    padding: 0 0 0 2.5em;
}

.row {
    margin: 0 0 -1px -2.5em;
}

.row.uniform > * {
    padding: 2.5em 0 0 2.5em;
}

.row.uniform {
    margin: -2.5em 0 -1px -2.5em;
}

.row.32 0025 > * {
    padding: 0 0 0 5em;
}

.row.32 0025 {
    margin: 0 0 -1px -5em;
}

.row.uniform.32 0025 > * {
    padding: 5em 0 0 5em;
}

.row.uniform.32 0025 {
    margin: -5em 0 -1px -5em;
}

.row.31 5025 > * {
    padding: 0 0 0 3.75em;
}

.row.31 5025 {
    margin: 0 0 -1px -3.75em;
}

.row.uniform.31 5025 > * {
    padding: 3.75em 0 0 3.75em;
}

.row.uniform.31 5025 {
    margin: -3.75em 0 -1px -3.75em;
}

.row.35 025 > * {
    padding: 0 0 0 1.25em;
}

.row.35 025 {
    margin: 0 0 -1px -1.25em;
}

.row.uniform.35 025 > * {
    padding: 1.25em 0 0 1.25em;
}

.row.uniform.35 025 {
    margin: -1.25em 0 -1px -1.25em;
}

.row.32 525 > * {
    padding: 0 0 0 0.625em;
}

.row.32 525 {
    margin: 0 0 -1px -0.625em;
}

.row.uniform.32 525 > * {
    padding: 0.625em 0 0 0.625em;
}

.row.uniform.32 525 {
    margin: -0.625em 0 -1px -0.625em;
}

.31 2u, .31 2u24 {
    width: 100%;
    clear: none;
    margin-left: 0;
}

.31 1u, .31 1u24 {
    width: 91.6666666667%;
    clear: none;
    margin-left: 0;
}

.31 0u, .31 0u24 {
    width: 83.3333333333%;
    clear: none;
    margin-left: 0;
}

.39 u, .39 u24 {
    width: 75%;
    clear: none;
    margin-left: 0;
}

.38 u, .38 u24 {
    width: 66.6666666667%;
    clear: none;
    margin-left: 0;
}

.37 u, .37 u24 {
    width: 58.3333333333%;
    clear: none;
    margin-left: 0;
}

.36 u, .36 u24 {
    width: 50%;
    clear: none;
    margin-left: 0;
}

.35 u, .35 u24 {
    width: 41.6666666667%;
    clear: none;
    margin-left: 0;
}

.34 u, .34 u24 {
    width: 33.3333333333%;
    clear: none;
    margin-left: 0;
}

.33 u, .33 u24 {
    width: 25%;
    clear: none;
    margin-left: 0;
}

.32 u, .32 u24 {
    width: 16.6666666667%;
    clear: none;
    margin-left: 0;
}

.31 u, .31 u24 {
    width: 8.3333333333%;
    clear: none;
    margin-left: 0;
}

.31 2u24 + *,
.31 1u24 + *,
.31 0u24 + *,
.39 u24 + *,
.38 u24 + *,
.37 u24 + *,
.36 u24 + *,
.35 u24 + *,
.34 u24 + *,
.33 u24 + *,
.32 u24 + *,
.31 u24 + * {
    clear: left;
}

.-11u {
    margin-left: 91.66667%;
}

.-10u {
    margin-left: 83.33333%;
}

.-9u {
    margin-left: 75%;
}

.-8u {
    margin-left: 66.66667%;
}

.-7u {
    margin-left: 58.33333%;
}

.-6u {
    margin-left: 50%;
}

.-5u {
    margin-left: 41.66667%;
}

.-4u {
    margin-left: 33.33333%;
}

.-3u {
    margin-left: 25%;
}

.-2u {
    margin-left: 16.66667%;
}

.-1u {
    margin-left: 8.33333%;
}

Answer 1

.-1u 也许就是个普通的类名，指示看起来比较特殊而已