message: Handle responsive sizing for channel group
diff: border-top 1px solid bordergray
  display flex
  padding (unit * 2) 0
  + justify-content center
  +
  + @media (min-width:(block_width_mar * 3) + 20) and (max-width:(block_width_mar * 4) + 20)
  + .Block:nth-of-type(1n+4)
  + display none
  + @media (min-width:(block_width_mar * 2) + 20) and (max-width:(block_width_mar * 3) + 20)
  + .Block:nth-of-type(1n+3)
  + display none
  + @media (min-width:(block_width_mar * 1) + 20) and (max-width:(block_width_mar * 2) + 20)
  + .Block:nth-of-type(1n+2)
  + display none
  