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PostCSS Responsive Type

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PostCSS plugin for automagical responsive typography. Adds a responsive property to font-size, line-height and letter-spacing that generates complex calc and vw based font sizes.

Inspired by this post from @MikeRiethmuller, and Typographic.

Part of Rucksack - CSS Superpowers.

Responsive Type Demo

Quick start:
html {
  font-size: responsive;
Specify parameters:

Units can be in px, rem, or em. When using em units, be sure that the font-range is specified in em as well.

html {
  font-size: responsive 12px 21px; /* min-size, max-size */
  font-range: 420px 1280px; /* viewport widths between which font-size is fluid */
Expanded syntax:
html {
  font-size: responsive;
  min-font-size: 12px;
  max-font-size: 21px;
  lower-font-range: 420px;
  upper-font-range: 1280px;
Responsive line-height and letter-spacing:

PostCSS Responsive Type also allows you to set fluid sizes for the line-height and letter-spacing properties. They have the same syntax and work the same way as responsive font sizes.

html {
  line-height: responsive 1.2em 1.8em;
  line-height-range: 420px 1280px;
  /* or extended syntax: */
  line-height: responsive;
  min-line-height: 1.2em;
  max-line-height: 1.8em;
  lower-line-height-range: 420px;
  upper-line-height-range: 1280px;
html {
  letter-spacing: responsive 0px 4px;
  letter-spacing-range: 420px 1280px;
  /* or extended syntax: */
  letter-spacing: responsive;
  min-letter-spacing: 0px;
  max-letter-spacing: 4px;
  lower-letter-spacing-range: 420px;
  upper-letter-spacing-range: 1280px;

Note: Unitless line heights are not supported.



To get started you only need to specify the responsive property, all other values have sane defaults.

  • min-font-size: 14px

  • max-font-size: 21px

  • lower-font-range: 420px

  • upper-font-range: 1280px

  • min-line-height: 1.2em

  • max-line-height: 1.8em

  • lower-line-height-range: 420px

  • upper-line-height-range: 1280px

  • min-letter-spacing: 0px

  • max-letter-spacing: 4px

  • lower-letter-spacing-range: 420px

  • upper-letter-spacing-range: 1280px


Browser Support

postcss-responsive-type just uses calc, vw units, and media queries behind the scenes, so it works on all modern browsers (IE9+). Although Opera Mini is not supported.

Legacy browsers will ignore the output responsive font-size. You can easily provide a simple static fallback:

.foo {
  font-size: 16px;
  font-size: responsive;

Alternatively, if you feel the need to fully support legacy browsers or Opera Mini, there are polyfills that can help!



postcss([ require('postcss-responsive-type')() ])

See PostCSS docs for examples for your environment.

You can use postcss-responsive-type with Stylus through PostStylus.



MIT © Sean King