A neural network in pure CSS

Draw a digit. A 64→64→32→10 network (6,570 integer weights) reads it using only @property, calc(), :has() and exp(). 0 bytes of JavaScript.

Press and drag on the gridTap cells to paint them, any size, anywhere.
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Inside the network

Every cell below is a CSS custom property, recomputed by the browser each time a pixel changes.

Scaled to fit8×8 input
Layer 164 units
Layer 232 units
0123456789
Scoresone per digit