.popper(@arrow, @arrow-width, @arrow-distance, @bg) {
    display: block;
    visibility: visible;
    font-size: @font-size-base;
    line-height: @line-height-base;
    position: absolute;
    z-index: @zindex-tooltip;

    &[x-placement^='top'] {
        padding: @arrow-width 0 @arrow-distance 0;
    }
    &[x-placement^='right'] {
        padding: 0 @arrow-width 0 @arrow-distance;
    }
    &[x-placement^='bottom'] {
        padding: @arrow-distance 0 @arrow-width 0;
    }
    &[x-placement^='left'] {
        padding: 0 @arrow-distance 0 @arrow-width;
    }

    &[x-placement^='top'] .@{arrow} {
        bottom: @arrow-distance - @arrow-width;
        border-width: @arrow-width @arrow-width 0;
        border-top-color: @bg;
    }
    &[x-placement='top'] .@{arrow} {
        left: 50%;
        margin-left: -@arrow-width;
    }
    &[x-placement='top-start'] .@{arrow} {
        left: 16px;
    }
    &[x-placement='top-end'] .@{arrow} {
        right: 16px;
    }

    &[x-placement^='right'] .@{arrow} {
        left: @arrow-distance - @arrow-width;
        border-width: @arrow-width @arrow-width @arrow-width 0;
        border-right-color: @bg;
    }
    &[x-placement='right'] .@{arrow} {
        top: 50%;
        margin-top: -@arrow-width;
    }
    &[x-placement='right-start'] .@{arrow} {
        top: 8px;
    }
    &[x-placement='right-end'] .@{arrow} {
        bottom: 8px;
    }

    &[x-placement^='left'] .@{arrow} {
        right: @arrow-distance - @arrow-width;
        border-width: @arrow-width 0 @arrow-width @arrow-width;
        border-left-color: @bg;
    }
    &[x-placement='left'] .@{arrow} {
        top: 50%;
        margin-top: -@arrow-width;
    }
    &[x-placement='left-start'] .@{arrow} {
        top: 8px;
    }
    &[x-placement='left-end'] .@{arrow} {
        bottom: 8px;
    }

    &[x-placement^='bottom'] .@{arrow} {
        top: @arrow-distance - @arrow-width;
        border-width: 0 @arrow-width @arrow-width;
        border-bottom-color: @bg;
    }
    &[x-placement='bottom'] .@{arrow} {
        left: 50%;
        margin-left: -@arrow-width;
    }
    &[x-placement='bottom-start'] .@{arrow} {
        left: 16px;
    }
    &[x-placement='bottom-end'] .@{arrow} {
        right: 16px;
    }
}