addFirst method

  1. @override
void addFirst (String rule)

Inserts a CSS rule at the beginning of this stylesheet.

This is useful for @import rules.

Implementation 

@override
void addFirst(String rule) {
  if (!isDev) {
    _sheet.insertRule(rule, 0);
  } else {
    _styleEl.insertBefore(new Text(rule), _styleEl.firstChild);
  }
  _ruleCounter++;
}