Window in the Fog: Timtoab shows us the Sudoku way

Today's Video:

Dynamic fog, my favourite type of fog. Another excellent addition to this variant!

Link to Play:

Window in the Fog by Timotab https://sudokupad.app/ng74gn1tru

Rules:

Normal Sudoku Rules Apply. Place the digits 1-9 in every row, column, and box, without repetition.

Dynamic fog: The grid is partially covered in fog. When all initially-unfogged cells have correct digits, the fog in the rest of the puzzle will clear. No guessing is necessary.

Extra regions: The four shaded 3x3 areas are extra regions. Digits cannot repeat within each such region.

Thermometers: Digits along a thermometer strictly increase from the bulb end.

Kropki: Where digits are separated by a white dot they are consecutive. Where digits are separated by a black dot, one is double the other. Not all dots are necessarily given.