I set out to make the keyboard actually look like the design I’d settled on.Everything worked by then but it still wore a generic light theme, and the wholepitch is a keyboard that looks and types like Samsung’s, so the look had to land. Ipulled every color and a few sizing numbers into one theme object and repaintedthrough it: a black keyboard, near-black keys, white letters, and red used for onething only, the key you’re pressing. On top of that I added the pieces the mockupshowed — a floating preview of the letter above your finger, a permanent numberrow, a dim symbol in the corner of every key that you get by long-pressing, atwo-page ?123 layer, a blue enter key that turns into a magnifier in search boxes, arow of toolbar icons up top, and holding the spacebar to slide the cursor throughtext.
The part I was wary of was the number row, because it doesn’t just sit on top, itgoes into the same grid the autocorrect uses to read where your taps land. Adding a fifth row shifts every letter’s position, and the worry was that it would quietlythrow off the typo-fixing and start mangling words. It turned out not to matter: thedecoder measures distances in key-widths rather than pixels, so adding oneevenly-sized row leaves the spacing between letters exactly what it was, and thedigits aren’t letters so they never enter the word search at all. The offline testthat runs thousands of fake typos came back with the same numbers as before thechange, false corrections still at zero, which is what let me put the row in the reallayout instead of bolting it on as a separate strip.
The screenshot shows the new black keyboard with the number row on top and a pressedkey lit red with its letter popped up above it.

Note, found while testing the redesign and not caused by it: two things in the decoder are worth fixing later. The bar offers “дом ас” when you type “домас”,because the run-together splitter will break a word in two as long as both halves are real, and “ас” happens to be a real word, so it peels it off even though that’s almost never what you want. And “домасний” won’t correct to “домашний”: that’s aс-for-ш mistake, but с and ш sit on opposite rows of the keyboard, and the auto correct only ever considers the key you hit and its close neighbors, so it never even weighsш as a possibility. The first is a small tuning fix; the second would mean teaching it to consider letter swaps beyond fat-finger range, which is a real feature and has to be done without breaking the zero-false-correction rule.
( the toolbar icons along the top aren’t wired up yet. The language one switches keyboards, but emoji, clipboard, settings, and the overflow menu are drawn for now and don’t do anything — they’re waiting for future wiring)