popper($arrow, $arrow-width, $arrow-distance, $bg)
    display: block
    visibility: visible
    font-size: $font-size-small
    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