PostCSS Responsive Type

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.

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.

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Defaults

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

font-size

• min-font-size: 14px

• max-font-size: 21px

• lower-font-range: 420px

• upper-font-range: 1280px

line-height

• min-line-height: 1.2em

• max-line-height: 1.8em

• lower-line-height-range: 420px

• upper-line-height-range: 1280px

letter-spacing

• min-letter-spacing: 0px

• max-letter-spacing: 4px

• lower-letter-spacing-range: 420px

• upper-letter-spacing-range: 1280px

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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!

• respond for media query support.

• calc-polyfill for calc support.

• vminpoly for vw unit support.

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Usage

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

See PostCSS docs for examples for your environment.

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

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License

MIT © Sean King