（摘）前端整理（一）：公共样式提取

/* 禁止选中文本 */
.usn{
    -webkit-user-select:none;
    -moz-user-select:none;
    -ms-user-select:none;
    -o-user-select:none;
    user-select:none;
}
/* 浮动 */
.fl { float: left; }
.fr { float: right; }
.cf { zoom: 1; }
.cf:after {
    content:".";
    display:block;
    clear:both;
    visibility:hidden;
    height:0;
    overflow:hidden;
}

/* 元素类型 */
.db { display: block; }
.dn { display: none; }
.di { display: inline }
.dib {display: inline-block;}
.transparent { opacity: 0 }


/*文字排版、颜色*/
.f12 { font-size:12px }
.f14 { font-size:14px }
.f16 { font-size:16px }
.f18 { font-size:18px }
.f20 { font-size:20px }
.fb { font-weight:bold }
.fn { font-weight:normal }
.t2 { text-indent:2em }
.red,a.red { color:#cc0031 }
.darkblue,a.darkblue { color:#039 }
.gray,a.gray { color:#878787 }
.lh150 { line-height:150% }
.lh180 { line-height:180% }
.lh200 { line-height:200% }
.unl { text-decoration:underline; }
.no_unl { text-decoration:none; }
.tl { text-align: left; }
.tc { text-align: center; }
.tr { text-align: right; }
.tj { text-align: justify; text-justify: inter-ideograph; }
.wn { /* 强制不换行 */
    word-wrap:normal;
    white-space:nowrap;
}
.wb { /* 强制换行 */
    white-space:normal;
    word-wrap:break-word;
    word-break:break-all;
}
.wp { /* 保持空白序列*/
    overflow:hidden;text-align:left;white-space:pre-wrap;word-wrap:break-word;word-break:break-all;
}
.wes { /* 多出部分用省略号表示 , 用于一行 */
    overflow:hidden;
    word-wrap:normal;
    white-space:nowrap;
    text-overflow:ellipsis;
}
.wes-2 { /* 适用于webkit内核和移动端 */
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 2;
    overflow: hidden;
} 
.wes-3 {
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 3;
    overflow: hidden;
}
.wes-4 {
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 4;
    overflow: hidden;
}

/* 溢出样式 */
.ofh { overflow: hidden; }
.ofs {overflow: scroll; }
.ofa {overflow: auto; }
.ofv {overflow: visible; }

/* 定位方式 */
.ps {position: static; }
.pr {position: relative;zoom:1; }
.pa {position: absolute; }
.pf {position: fixed; }


/* 垂直对齐方式 */
.vt {vertical-align: top; }
.vm {vertical-align: middle; }
.vb {vertical-align: bottom; }


/* 鼠标样式 */
.csd {cursor: default; }
.csp {cursor: pointer; }
.csh {cursor: help; }
.csm {cursor: move; }

/* flex布局 */
.df-sb {
    display:flex;
    align-items: center;
    justify-content: space-between;
}
.df-sa {
    display:flex;
    align-items: center;
    justify-content: space-around;
}

/* 垂直居中 */
.df-c {
    display: flex;
    align-items: center;
    justify-content: center;
}
.tb-c {
    text-align:center;
    display:table-cell;
    vertical-align:middle;
}
.ts-c {
    position: absolute;
    left: 50%; top: 50%;
    transform: translate(-50%, -50%);
}
.ts-mc {
    position: absolute;
    left: 0;right: 0;
    bottom: 0; top: 0;
    margin: auto;
}

/* 辅助 */
.mask-fixed-wrapper {
    width: 100%;
    height: 100%;
    position: fixed;
    left:0;top:0;
    background: rgba(0, 0, 0, 0.65);
    z-index: 999;
}
.bg-cover {
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center center;
}
.bg-cover-all {
    background-size: 100% 100%;
    background-repeat: no-repeat;
    background-position: center center;
}

原文地址：https://segmentfault.com/a/1190000013041329
作者：咚子