virtualKeyboard.overlaysContent и env(keyboard-inset)

navigator.virtualKeyboard.overlaysContent = true позволяет контенту заезжать под клавиатуру; компенсируйте padding-bottom: env(keyboard-inset-height, 0px) на .brief-form.

Без API — fallback на visualViewport в JS.

- [VirtualKeyboard API — MDN](https://developer.mozilla.org/en-US/docs/Web/API/VirtualKeyboard_API) — overlaysContent и geometry.

- [keyboard-inset-* — Chrome Developers](https://developer.chrome.com/docs/web-platform/virtual-keyboard) — Документация Virtual Keyboard.