CSS Development Guide

Common guidelines

Write styling for your component with Sass syntax and save it with extension .scss. Each component module should only import styles from it's own dedicated sass file. Thus each import path should always begin with ./. For example:

// components/component.js

...
import styles from './component.scss';

...
  render() {
    return <div className={ styles.myDiv }/>>
  }

Class name in Sass files should be in camel case and begin with lower case character.
CSS classes that are there for the sole purpose of testing must begin with test--.
.css files can also be imported like .sass files but are not localized with CSS modules. They are global styles including those that are use by 3rd party libraries.
Inline styles can be used when more programmatic approach is required.
Sometime you will see something like:

height: 30px;
line-height: 29px;

This is to fulfill optical center, for more information please take a look at: https://services.math.duke.edu/education/ccp/resources/write/design/graphic7.html

Naming css color variables

Use web approx colors with postfix -color at the end, eg $black-10-color
rgba color should be name with the color name and alpha: [color-name]-[alpha]-color, eg $thunder-90-color
Find colors tool http://chir.ag/projects/name-that-color/