How can I implement CSS into React native - react-native

Question

I am either overthinking this or missing the core concepts of how CSS and html work within React Native.
I have this CSS code that I provided below that creates an inverted border radius tab like the tabs on google chrome.
I understand that you can use stylesheets in react native to implement CSS but I know these are formatted differently.
How can I implement this CSS code in a react native app? Snack io is a great tool to be able to quickly implement this if you would like to link your demo to me.
CSS
body {
background: #1c1c1c;
padding: 50px;
}
.tab {
float: left;
width: 90px;
padding: 10px 15px;
height: 30px;
position: relative;
background: #fff;
-webkit-border-top-left-radius: 10px;
-webkit-border-top-right-radius: 10px;
-moz-border-radius-topleft: 10px;
-moz-border-radius-topright: 10px;
border-top-left-radius: 10px;
border-top-right-radius: 10px;
}
.tab:before,
.tab:after {
content: "";
position: absolute;
height: 10px;
width: 20px;
bottom: 0;
}
.tab:after {
right: -20px;
border-radius: 0 0 0 10px;
-moz-border-radius: 0 0 0 10px;
-webkit-border-radius: 0 0 0 10px;
-webkit-box-shadow: -10px 0 0 0 #fff;
box-shadow: -10px 0 0 0 #fff;
}
.tab:before {
left: -20px;
border-radius: 0 0 10px 0;
-moz-border-radius: 0 0 10px 0;
-webkit-border-radius: 0 0 10px 0;
-webkit-box-shadow: 10px 0 0 0 #fff;
box-shadow: 10px 0 0 0 #fff;
}

Answer 1

You can make a file with js extension, example styles.js and then import the file with import MyStyles from 'YOUR_RUTE_FILE'
The other way is in the same file
import { StyleSheet } from 'react-native
And write your styles
const stylesRNP = StyleSheet.create({
body: {
//Styles...
}
});