How can I bind CTRL+SCROLL_UP to zoom-in?

LIke in vim-mode, I want CTRL+SCROLL to zoom in and out.

How can I add a binding for that?

@daltor there are several ways to achieve it. One possible way is to add the snippet below to your config:

(define-configuration :document-mode
  "Extend keybindings."
    (keymaps:define-keyscheme-map "my-document-mode" (list :import %slot-value%)
       "C-button4" 'zoom-page
       "C-button5" 'unzoom-page)
       "C-button4" 'zoom-page
       "C-button5" 'unzoom-page)))))

Your question prompted me to make a change when it comes to default keybindings, see mode/document: Bind common zoom keybindings to all keyschemes. · atlas-engineer/nyxt@bc11600 · GitHub.

In the next 3-series release, these keybindings will be enabled for all keyschemes.