暫定版
balloon(l, 20, red)
balloon(position, size, color)
position relative
border 1px solid color
background-color #FFF
border-radius 5px
&::before
&::after
content ""
position absolute
width 0
height 0
if(position == t)
&::before
&::after
left 50%
margin-left -(size/2)px
border-style none solid solid
border-width (size/2)px
&::before
top -(size/2)px
border-color transparent transparent color
&:after
top -(size/2 - 1)px
border-color transparent transparent #FFF
if(position == r)
&::before
&::after
top 50%
margin-top -(size/2)px
border-style solid none solid solid
border-width (size/2)px
&::before
right -(size/2)px
border-color transparent transparent transparent color
&:after
right -(size/2 - 1)px
border-color transparent transparent transparent #FFF
if(position == b)
&::before
&::after
left 50%
margin-left -(size/2)px
border-style solid solid none
border-width (size/2)px
&::before
bottom -(size/2)px
border-color color transparent transparent
&:after
bottom -(size/2 - 1)px
border-color #FFF transparent transparent
if(position == l)
&::before
&::after
top 50%
margin-top -(size/2)px
border-style solid solid solid none
border-width (size/2)px
&::before
left -(size/2)px
border-color transparent color transparent transparent
&:after
left -(size/2 - 1)px
border-color transparent #FFF transparent transparent