I've just released v0.1.15 of Textual, with Windows support.
The Windows support is somewhat experimental, but so far seems solid. You will get best results on the new Windows Terminal. On the classic command prompt you might find a reduced color palette. This works on VSCode, but is missing mouse input on Windows 10 due to an upstream issue which is apparently fixed in Windows 11. If you have Windows 11, I'd appreciate confirmation on that!