@styled-system/css

What is @styled-system/css?

@styled-system/css is a utility function for creating style objects based on a theme. It allows you to use a JavaScript object to define styles, which can then be applied to components. This package is part of the Styled System family and is designed to work seamlessly with other Styled System utilities.

What are @styled-system/css's main functionalities?

Theming

Theming allows you to define a set of design tokens (e.g., colors, spacing, typography) that can be referenced throughout your application. This ensures consistency and makes it easy to update the design system.

{
  "theme": {
    "colors": {
      "primary": "#07c",
      "secondary": "#05a"
    }
  },
  "styles": {
    "button": {
      "backgroundColor": "primary",
      "color": "white",
      "padding": "8px 16px",
      "borderRadius": "4px"
    }
  }
}

Responsive Styles

Responsive styles allow you to define different styles for different screen sizes using an array syntax. This makes it easy to create responsive designs without writing media queries.

{
  "styles": {
    "button": {
      "padding": ["8px 16px", "12px 24px", "16px 32px"]
    }
  }
}

Variant Styles

Variant styles allow you to define reusable style objects that can be applied to components. This is useful for creating consistent styles for different variants of a component (e.g., primary and secondary buttons).

{
  "theme": {
    "buttons": {
      "primary": {
        "backgroundColor": "primary",
        "color": "white"
      },
      "secondary": {
        "backgroundColor": "secondary",
        "color": "white"
      }
    }
  },
  "styles": {
    "button": {
      "variant": "buttons.primary"
    }
  }
}

Other packages similar to @styled-system/css

styled-components

styled-components is a library for styling React components using tagged template literals. It allows you to write actual CSS code to style your components. Compared to @styled-system/css, styled-components offers a more traditional approach to styling with CSS, but it lacks the built-in theming and responsive style utilities.

emotion

Emotion is a library designed for writing CSS styles with JavaScript. It provides both a CSS-in-JS solution and a styled-components-like API. Emotion offers similar theming and responsive style capabilities as @styled-system/css, but it also includes additional features like server-side rendering and source maps.

tailwindcss

Tailwind CSS is a utility-first CSS framework that provides low-level utility classes to build custom designs. Unlike @styled-system/css, which uses JavaScript objects for styling, Tailwind CSS uses predefined utility classes in your HTML. Tailwind CSS is highly customizable and can be configured to work with a design system, but it requires a different approach to styling compared to CSS-in-JS solutions.

README

@styled-system/css

Styled System for the css prop

npm i @styled-system/css

Styled System CSS lets you write style objects with responsive, theme-aware Styled System shortcuts.

// usage with the css prop
import React from 'react'
import css from '@styled-system/css'

const Beep = props =>
  <div
    {...props}
    css={css({
      fontSize: [4, 5, 6],
      color: 'primary',
    })}
  />

// usage with a styled HOC
import styled from '@emotion/styled'
import css from '@styled-system/css'

const Boop = styled('div')(
  css({
    fontSize: [ 4, 5, 6 ],
    color: 'primary',
    bg: 'gray',
    '&:hover': {
      color: 'secondary',
    },
  })
)

Theme Keys

The following keys in your style object will work the same as Styled System props, pulling values from your theme object.

Property	Theme Key
fontFamily	fonts
fontSize	fontSizes
fontWeight	fontWeights
lineHeight	lineHeights
letterSpacing	letterSpacings
color	colors
backgroundColor, bg	colors
margin, m	space
marginTop, mt	space
marginRight, mr	space
marginBottom, mb	space
marginLeft, ml	space
marginX, mx	space
marginY, my	space
padding, p	space
paddingTop, pt	space
paddingRight, pr	space
paddingBottom, pb	space
paddingLeft, pl	space
paddingX, px	space
paddingY, py	space
top	space
bottom	space
left	space
right	space
border	borders
borderTop	borders
borderRight	borders
borderBottom	borders
borderLeft	borders
borderColor	colors
borderWidth	borderWidths
borderStyle	borderStyles
borderRadius	radii
boxShadow	shadows
textShadow	shadows
zIndex	zIndices
width	sizes
minWidth	sizes
maxWidth	sizes
height	sizes
minHeight	sizes
maxHeight	sizes
size	sizes

Responsive Arrays

All CSS properties accept arrays as values for responsive styles.

<div
  css={css({
    fontSize: [ 4, 5, 6 ],
  })}
/>

In this example, fontSize accepts an array, picking up values from the theme.fontSizes scale, and borderBottom is passed through as plain CSS.

<div
  css={css({
    // Styled System key
    fontSize: [ 3, 4, 5 ],
    // CSS property
    borderBottom: '2px solid tomato',
  })}
/>

MIT License