Bare minimum html to get you started.
A simple grid option that works, even in IE.
Tables of contents pre-noted for keeping organized.
Brief normalize at the start of the main CSS.
The media query desktop and mobile. You specify the column width by the number / 12
Desktop: c12, c6, c4, etc. 12 is full width, 6 is 50%, and so on.
Mobile: s12, s6, s4, etc. 12 is full width, 6 is 50%, and so on.
The last row is c3 for desktop and s6 for mobile, resize to see.
All 12 columns
6
6
4
4
4
c3 s6
c3 s6
c3 s6
c3 s6