Quick CSS setter

stylePage.js

function stylePage(d){
  for (var selector in d) {
    if (!d.hasOwnProperty(selector)) return;
    var properties = d[selector];
    for (var styleName in properties) {
      if (!properties.hasOwnProperty(styleName)) return;
      var style = properties[styleName];
      var matching = document.querySelectorAll(selector);
      for (var j = 0; j < matching.length; j++) {
        matching[j].style[styleName] = style;
      }
    }
  }
}
/*
Example:
stylePage({
  '.my-class child': {
    color: 'red',
  },
})
*/