Suggestions Please: An Easy to Use Mac Compatible Text/Html Editor That Is Compatible with Steemit

Hi everyone.  I'm enjoying using Steemit but have found that the interface leaves a lot to be desired in regards to text formatting, composition etc.  I was wondering if there anyone has any recommendations for a html editor that would allow formatting and construction of posts prior to posting on here?  

The features I'm looking for are:

1. Mac compatibility
2. Reasonable price or open source
3. More flexibility than that offered by the Steemit web interface but not overly complex
4. Steemit integration (although probably too early for that)
5. Some basic photo editing features such as resizing or cropping
6. More advanced text formatting via GUI (like a word processor)

Thanks,

AA.