Customization for the media query breakpoints would be great

[jamesinvt]

First of all, love this project! Thanks for the work you've put into it.

However, one issue I've run across is using chota for a chrome extension. Trying to keep the width 400-500 pixels which I find myself having to manually override many of the media queries you have hard coded. Having some variables like --breakpoint-small --breakpoint-medium --breakpoint-large or something similar where we can control the breakpoints would be very helpful!

Here's an example of a media query getting in my way

@media screen and (max-width: 599px) {
    .container {
        width:100%
    }

    .col,[class*=col-],[class^=col-] {
        -webkit-box-flex: 0;
        -ms-flex: 0 1 100%;
        flex: 0 1 100%; // this lil bugger
        max-width: 100%
    }
}