CSS logical properties should be used to create flexible, internationalization-friendly styles by adapting to text flow instead of fixed directions. They replace physical properties like margin-left with logical terms like margin-inline-start, which adjust automatically based on writing mode. Common mappings include margin-block-start for margin-top and margin-inline-end for margin-right, with shorthand options like margin-block and padding-inline. These properties are ideal for multilingual sites, component libraries, and modern layouts like Flexbox and Grid, offering future-proof styling with strong current browser support.
CSS logical properties are a modern way to style elements based on their direction and layout flow, rather than fixed physical directions like left, right, top, or bottom. They help developers write more flexible and internationalization-friendly styles by abstracting positioning and spacing based on writing mode.

Why Use Logical Properties?
Traditional CSS uses physical directions — for example, margin-left
or padding-right
. But when dealing with different writing modes (like right-to-left languages such as Arabic or vertical scripts like Japanese), these values don’t always make sense. Logical properties solve this by using terms like block and inline, which adapt depending on how the text flows.
For instance:

-
margin-block-start
replacesmargin-top
in horizontal writing modes. - In a vertical writing mode, it might affect the side of the element instead.
This makes your CSS more adaptable without needing extra rules for different languages or layouts.
Common Logical Property Mappings
Here’s how some common physical properties translate into logical ones:

-
margin-top
→margin-block-start
-
margin-bottom
→margin-block-end
-
margin-left
→margin-inline-start
-
margin-right
→margin-inline-end
Same pattern applies to:
padding
border
-
size
(likewidth
andheight
in block and inline directions)
You can also use shorthand versions:
-
margin-block: 1em 2em;
sets both start and end in block direction -
padding-inline: 0.5em 1em;
does the same for inline direction
These properties respond correctly when you change the writing-mode
or direction
of an element or document.
When Should You Use Them?
You don’t need to switch all your CSS to logical properties, but they’re especially useful in:
- Multilingual websites where layout direction changes
- Components that should respect user-defined writing modes
- Modern layout techniques like Flexbox and Grid, where block/inline behavior matters
If you're building a component library or theming system, adopting logical properties helps avoid hardcoding assumptions about text flow.
They’re not complicated once you get used to thinking in block and inline directions. And while browser support is solid now (Chrome, Firefox, Safari, Edge all support them well), it's still worth checking if you need to support older browsers.
But if you're starting fresh or working on a modern project, giving them a try can future-proof your styles a bit.
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