word-spacing doesn't get adjusted properly in Safari

[j0hj0h]

I get fine results for all browsers except Safari (mobile and desktop). I know it doesn't have subpixel font-scaling, but the adjustement via word-spacing could be much more accurate. Mostly it's left untouched. I see many cases of inaccurate adjusted lines, where manual word-spacing leads to much better results.

[j0hj0h]

I fixed it. I'll create a pull request later.