CSS Logical Properties and Values is a module of CSS introducing logical properties and values that provide the ability to control layout through logical, rather than physical, direction and dimension mappings.

The module also defines logical properties and values for properties previously defined in CSS 2.1. Logical properties define direction‐relative equivalents of their corresponding physical properties.

Block vs. inline

Logical properties and values use the abstract terms block and inline to describe the direction in which they flow. The physical meaning of these terms depends on the writing mode.

Block dimension
The dimension perpendicular to the flow of text within a line, i.e., the vertical dimension in horizontal writing modes, and the horizontal dimension in vertical writing modes. For standard English text, it is the vertical dimension.
Inline dimension
The dimension parallel to the flow of text within a line, i.e., the horizontal dimension in horizontal writing modes, and the vertical dimension in vertical writing modes. For standard English text, it is the horizontal dimension.

Reference

Properties

Guides

Specifications

Specification Status Comment
CSS Logical Properties and Values Level 1 Editor's Draft Initial definition.

Browser compatibility

In general:

  • Firefox has support for the mapped properties — where there is a direct mapping from the physical to the logical version.
  • Chrome, from version 69, has support for the mapped properties.
  • Edge currently has no support.
  • Some new shorthand properties currently have no support in any browser.

See the individual property pages for full compatibility information.

Document Tags and Contributors

Last updated by: chrisdavidmills,