Mithril + j2c

widget.js

Widget = {
  styles: j2c.scoped({
    title: {
      font_size: '3rem',
      "&:before":{
        color: "#888",
        content: "#"
      }
    },
    content: {
      padding: '2rem',
      margin: '0 0 0.5rem 0'
    }
  }),

  view: function (ctrl) {
    return m('.widget', [
      m('style', {config:function(el, isInit){
        if (isInit) {
          // if no IE lte8 support is required `m('style', Widget.styles)`
          // does the trick.
          try { el.innerText = Widget.styles }
          catch (e) { el.styleSheet.cssText = Widget.styles }
        }
      })
      m('h3', { class: Widget.styles.title }),
      m('div', { class: Widget.styles.content })
    ])
  }
}