# Problem when compiling stylesheets

Hello there,
I’ve just downloaded Grafana 5.4.3 contanier and I’m testing it. No problem so far.
I need to modify the css (let’s say: the background color), so I edited the public/sass/_variables.dark.scss.
Then, as far as I read, I have to compile the assets running
`yarn start`

But I get this error
`Couldn't find a package.json file in "/usr/share/grafana"`

Indeed, this file is missing.
I think it should be a quite easy task… so, is there something I didn’t get?

don’t you have to build frontend with yarn watch / dev ?