Here is a five minute chart of today's e-mini trading. I now think the day's high has been seen at 795. My estimate for the day's low is 770 (blue rectangle). The purple dotted line is midpoint support based on a previous reaction from 801 to 761. I expect the e-minis to bounce from there back to midpoint resistance near the dashed red line.
Volume so far on this decline has remained relatively low and this is consistent with my view that the drop from 830 is just a reaction in a continuing up trend.