xs sm md lg xl xxl

grid - inner

Column #1 col-12 col-md-6
Inner Column #1 col-12 col-md-6
Inner Column #2 col-12 col-md-6
Column #2 col-12 col-md-6
Inner Column #1 col-12 col-md-6
Inner Column #2 col-12 col-md-6