a11y: keyboard navigation for django foto upload

[CarolingerSeilchenspringer]

URL: https://meinberlin-dev.liqd.net/ideas/create/module/brainstorming-16/
user: user only using keyboard
expected behaviour: I can clearly see focus of both field and icon. Hitting enter on the icon opens my local finder.
behaviour: focus not seen cleary (field) or nor at all (icon). Enter on icon saves form.
important screensize:
device & browser: tested on Mac chrome/firefox
Comment/Question: django foto upload is for ideas and proposals (user), for plans as well as in dashborad (hero and tile picture)

Screenshot?