adding global stylesheet gatsby

I created a gastby site using their doc

and would like to add some global style (without a layout component) as per this doc.

I'd like to add this to my current repository which is essentially the starter kit.

I've created the global.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    min-height: 100vh;
}

and the gatsby-browser.js files

import "./src/styles/global.css"

but no changes are reflected.

What am i missing?