Node in bar size

why the common bar size is so large ?
how can i ajdust this?
thanks

Because that is the design of the page.

You would have to create some custom CSS to override the style of the editor. You can use the editorTheme setting to get the editor load a custom CSS file:

https://nodered.org/docs/user-guide/runtime/configuration#editor-themes

editorTheme: {
    page: {
        css: "/absolute/path/to/custom/css/file",
    }
}

thanks you !