target buttons-like element

hello,
i installed a new theme on my blog.
your plugin looks good but there’s one thing bothering me
i need your plugin’s button to use the font of my theme
which isn’t the case

https://ibb.co/5WDkXLT

i want all buttons like element (search bar, edit/publish, browse files) to have the font of my theme using font-family: inherit. how can i easily target all those elements in css? many thanks

The page I need help with: [log in to see the link]