Neutron works with all modern browsers. This includes Internet Explorer 9 and later. Generally, if the browser supports the :nth-child and :nth-of-type pseudo-selectors, and the calc() property, Neutron should work fine on that browser.
Neutron was developed and tested using version 3.4.18 of Sass. Neutron uses many recent features of Sass so it is recommended to use the lastest version of sass possible.
Neutron has no hard-coded limits to the number of columns you can have, however in some extreme situations, your layout might not display correctly. When trying to fit many columns in a small container, you can begin to encounter subpixel rounding errors. This can lead to columns not filling their container if a browser decided to round down to the nearest pixel for all the columns. This issue usually only occurs when dealing with a large number of columns only a few pixels wide.
$target to target any kind of element?The $target feature for the columns() mixin uses the CSS pseudo selectors :nth-child and :nth-of-type. Due to limitations with these selectors, generally you should only target element types, classes, or element and class combinations that target only one type of element (eg. <div>, <section>, <span>). If you target a class that is applied to different types of elements, unexpected behavior and layout can occur.
Neutron is open source and we'd gladly accept pull requests for bug fixes or minor improvements to Neutron. For larger feature additions, acceptance will be decided on a case by case basis for their suitability for Neutron and the direction we want to take it.