preset

.ellipsis() {
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
}
.clear() {
    &:after {
        content: '';
        display: block;
        height: 0;
        clear: both;
    }
}
.border-box() {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}
.horizontal-flex() {
    display: -webkit-box;
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -webkit-box-orient: horizontal;
    -moz-box-orient: horizontal;
    -webkit-flex-direction: row;
    -ms-flex-direction: row;
    flex-direction: row;
}
.vertical-flex() {
    display: -webkit-box;
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -webkit-box-orient: vertical;
    -moz-box-orient: vertical;
    -webkit-flex-direction: column;
    -ms-flex-direction: column;
    flex-direction: column;
}
.flex(@grow, @shrink) {
    -webkit-box-flex: @grow;
    -moz-box-flex: @grow;
    -webkit-flex: @grow @shrink auto;
    -ms-flex: @grow @shrink auto;
    flex: @grow @shrink auto;
}
.transform(@trans) {
    -webkit-transform: @trans;
    -moz-transform: @trans;
    transform: @trans;
}
.justify-content(center) {
    -webkit-box-pack: center;
    -webkit-justify-content: center;
    justify-content: center;
}
.align-items(center) {
    -webkit-box-align: center;
    -moz-box-align: center;
    -webkit-align-items: center;
    -ms-flex-align: center;
    align-items: center;
}
.placeholder-color(@color) {
    &::-webkit-input-placeholder { /* WebKit browsers */
        color:    @color;
    }
    &:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
        color:    @color;
        opacity:  1;
    }
    &::-moz-placeholder { /* Mozilla Firefox 19+ */
        color:    @color;
        opacity:  1;
    }
    &:-ms-input-placeholder { /* Internet Explorer 10+ */
        color:    @color;
    }
}
.transition(@trans) {
    -webkit-transition: @trans;
    -moz-transition: @trans;
    -ms-transition: @trans;
    -o-transition: @trans;
    transition: @trans;
}
.user-select(@sel) {
    -webkit-user-select: @sel;
    -moz-user-select: @sel;
    -ms-user-select: @sel;
    user-select: @sel;
}
.box-shadow(@shadow) {
    -webkit-box-shadow: @shadow;
    -moz-box-shadow: @shadow;
    box-shadow: @shadow;
}