=btn-border-color(!color)
   border-color= darken(!color, 25)
 
 =btn-text-shadow(!color)
   !text_shadow = darken(!color, 25)
   text-shadow= !text_shadow  "1px 1px 1px"
 
 =btn-style(!color)
   !color1 = lighten(!color, 30)
   !color2 = darken(!color, 20)
   +h-linear-gradient(!color1, !color2)
   background-color= !color
   +btn-border-color(!color)
   +btn-text-shadow(!color)
 
 =btn-style-hover(!color)
   !color = lighten(!color, 8)
   !color1 = lighten(!color, 22)
   !color2 = darken(!color, 38)
   +h-linear-gradient(!color1, !color2)
   background-color= !color
   +btn-border-color(!color)
   +btn-text-shadow(!color)
 
 =btn-style-active(!color)
   !color = darken(!color, 5)
   !color1 = lighten(!color, 25)
   !color2 = darken(!color, 35)
   +h-linear-gradient(!color1, !color2)
   background-color= !color
   +btn-border-color(!color)
   +btn-text-shadow(!color)
 
 =btn-structure(!font_size, !border_width, !line_height = !font_size *1.2)
   !v_padding = floor(!font_size/2.5)
   !h_padding = floor(!font_size)
   !v_padding_active = !v_padding - 1px
   !h_padding_active = !h_padding - 1px
   border-width= !border_width
   font-size= !font_size
   padding= !v_padding !h_padding
   line-height= !line_height
   &:active
     border-width= !border_width + 1px
     padding= !v_padding_active !h_padding_active