CSSGrid and Responsive Layout

I trying to get the CSSGrid/CSSGridItem controls to change the number of fixed width GridItems displayed per row as the screen is rotated or chrome browser window is narrowed. What are the properties that control this response, as I’ve tried a lot of combinations and the GridItems do not move down to the next row for me as the screen narrows.

Let me answer my own question: In the CSSGrid control, the display property. I changed it from grid to blank, and now they seem to react as expected.

And the height and especially width must be set to auto.

Feel free to add tips to the Wiki page if you feel it will help others.