320 (320-479), 480 (480-767), 768 (768-959)
Grids we use can be divided as such:
They can also be padded like so:
They can be put together in any combination that adds up to 100 (99 rounds up to 100):
You can also remove the gutters from the columns:
You can divide up a columns to go to the top or bottom:
66.666% middle, full @480px
Shrink the screen to below 767 to see how these wrap differently.
66.666% middle, full @320px
75% middle, full @480px
75% full @768px
And, of course, you can simply make columns disappear at our breakpoints as well.
Hide @768px and below
B. Hide A @768px
B. Hide C @768px
Hide @480px and below
B. Hide A @480px
B. Hide C @480px
Hide @320px and below
B. Hide A @320px
B. Hide C @320px
Lastly, here are some crazy stacked examples:
NOTE: IE8 does NOT support media queries, so columns never collapse to full width.