This doesn't work for me on Firefox Mobile on Android at 10x10 or above. It's as if the touch targets get too small to select: I can click on the numbers to turn them red, but I can't seem to select any square.
Works well on smaller sizes and on Chrome on the same device.
Thanks, weird one - I just put in a fix, you can refresh the page to get it. Some kind of CSS glitch where the cells (<i> elements) got a height of 0 at narrow screen sizes, in Firefox only, despite those and their parent <td>s having an explicit height. Just added an absolute positioning hack to fix it.
Didn't see the old way but I'm having no issues on Firefox Android as of now. I really like the checkpoint thing. It's something I've craved from other platforms. I will note though that the 4 with the like through it (maybe just my phone) is just a 4 (the line ends up being the crossbar of the 4). Maybe a diagonal line would be better?
Think this is fixed now - in dark mode, the numbers didn't gray out properly like in light mode. On some browsers the strikethru lines up with the 4, but the additional graying out hopefully communicates the same thing.
Works well on smaller sizes and on Chrome on the same device.