npm install @csstools/postcss-logical-overscroll-behavior --save-dev

PostCSS Logical Overscroll Behavior lets you use overscroll-behavior-inline and overscroll-behavior-block properties following the CSS Overscroll Specification.

.inline {
	overscroll-behavior-inline: auto;
}
.block {
	overscroll-behavior-block: contain;
}
/* becomes */
.inline {
	overscroll-behavior-x: auto;
}
.block {
	overscroll-behavior-y: contain;
}

Usage

Add PostCSS Logical Overscroll Behavior to your project:

npm install postcss @csstools/postcss-logical-overscroll-behavior --save-dev

Use it as a PostCSS plugin:

const postcss = require('postcss');
const postcssLogicalOverscrollBehavior = require('@csstools/postcss-logical-overscroll-behavior');
postcss([
	postcssLogicalOverscrollBehavior(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);

PostCSS Logical Overscroll Behavior runs in all Node environments, with special instructions for:

Options

inlineDirection

The inlineDirection option allows you to specify the direction of the inline axe. The default value is left-to-right, which would match any latin language.

You should tweak this value so that it is specific to your language and writing mode.

postcssLogicalOverscrollBehavior({
	inlineDirection: 'top-to-bottom'
})

.inline {
	overscroll-behavior-inline: auto;
}
.block {
	overscroll-behavior-block: contain;
}
/* becomes */
.inline {
	overscroll-behavior-y: auto;
}
.block {
	overscroll-behavior-x: contain;
}

Each direction must be one of the following:

top-to-bottom
bottom-to-top
left-to-right
right-to-left