Hi, I believe using [class=^col-] will lead to some problems:

1. If col- is not at the start of a class name, like class=" col-md-6" or class="first-xs col-md-6", then it will mismatch the selector.
2. When using css-loader, [class=^col-] won't be exported, because css-loader's CSS Module only works with class name selector. A typical user is react-flexbox-grid. I just posted a related issue there.

I'm thinking that maybe we could keep [class=^col-] and add all the explicit class names back?

Thank you!