Row-rule-width - CSS Property

row-rule-width

Summary of characteristics of the row-rule-width property

Quick description
Defines the thickness of the line separation traits in a grid container or flex-box container context.
Status
Compatibility issues ⚠
Predefined values
medium | thin | thick
Percentages
Not applicable.
Initial value
medium
Inherited by default
No.
Animation type
Computed value: during an animation, the row-rule-width property gradually changes from one value to another.
Canonical order
Per grammar: serialization in the order of syntax.
W3C Module
CSS Gap Decorations Module.
References (W3C)
Document status: WD (Working Draft)

Syntax diagram of row-rule-width.

row-rule-width - Syntax DiagramSyntax diagram of the row-rule-width CSS property. Specifies the thickness of the lines for the line separation borders. thick thick thin thin medium medium width width , ,row-rule-width:;row-rule-width:;
Syntax diagram of the row-rule-width property.
The links in the diagram provide more details about the values.
Download the diagram in SVG.

In the diagram, the bold terms are the predefined words of CSS, the other terms are described below:

  • width is a positive or zero numerical value followed by a CSS dimension units.
  • You can repeat the value by separating it with a comma.

Description of the row-rule-width property.

⚠
This property is experimental. For now, major browsers still don't recognize it (2026).

row-rule-width sets the thickness of the borders between lines, in a grid or a flex-box. This can be a predefined value or a numeric value. It is possible to give multiple values (separated by commas).

The thickness of the line doesn't add to the gap width (defined by row-gap): adding a line doesn't space the rows any further.

This property is exactly the opposite of column-rule-width. Also see shorthand property row-rule. For a summary on gap decorations, see rule.

Values for row-rule-width.

⚠ The examples still don't work on Firefox   (2026).

  • row-rule-width: 3px;

    A positive number or zero, followed by a unit of dimension (see CSS dimension units). The following predefined values can also be used (the numérical equivalents may differ slightly from one browser to another):

    • thin : about 1 pixel.
    • medium : about 4 pixels (initial value).
    • thick : about 5 pixels.
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    row-rule:medium;
  • row-rule-width: 3px, 6px, 15px; row-rule-width: repeat(3, thin), medium;

    A list of comma-separated values. Each value is assigned to a horizontal stripe. If the number of stripes is greater than the number of values, the list starts over from the beginning. The repeat() function is accepted, especially useful when the number of stripes is large.

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    row-rule:repeat(2, thin), 6px;
  • row-rule-width: initial; (medium) row-rule-width: inherit; row-rule-width: revert; row-rule-width: revert-layer; row-rule-width: revert-rule; row-rule-width: unset;

    Common values ​​are presented on these pages: initial, inherit, revert, revert-layer, revert-rule, unset.

Animation of the row-rule-width property.

We’re offering you an animation on a flex container and another on a grid container.

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Simulator.

The example below is built on a flexbox. Besides choosing the value for row-rule-width, you can adjust the size of the container.

row-rule-width :
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Browsers compatibility with row-rule-width.

For now (2026), only Chrome  , Edge  , and a few other browsers handle this row-rule-width property correctly.

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Support for the row-rule-width property, which sets the thickness of the row separators in a grid, flex-box, etc.
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row-rule-width
property
Estimated overall support.
57%

Browsers on computers :

Mobile browsers :

Outdated or marginal browsers :

Internet Explorer

UC Browser pour Androïd

Opéra Mobile

QQ Browser

Baidu Browser

Safari

Safari sur IOS

Opéra

Chrome

Edge

Firefox

Chrome pour Androïd

Samsung Internet

Androïd Brower

Firefox pour Androïd

KaiOS Browser

Opéra mini

See Caniuse.com for more compatibility information.
Caniuse

Historic of the row-rule-width property.

  • CSS Gap Decorations Module Level 1.

    This module covers the rules that define gutters between columns in a multi-column container (grid, flex-box...). It extends these possibilities to gutters between elements arranged in multiple rows, allowing these features to be used on other types of containers. Several properties define how these gutters should be drawn.

    Regarding row-rule-width Extension of the property column-rule-width to define the thickness of the separating lines, in the context of a grid container or a flex-box container.
    WD
    April 17, 2025
    Working Draft.
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See also, about gap decorations.

The newly created CSS Gap Decorations Module. sets all the properties related to decorative borders, in the context of a grid container, flex-box, or any other container that displays blocks in rows or columns. These properties are the following:

Properties:

⚠
column-rule-break
Defines how the column separator lines behave at intersections with the row separator lines.
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column-rule-inset
Sets the spacing at the ends of the column separation lines (in a grid container or any other container that displays blocks in columns).
⚠
column-rule-visibility-items
Sets whether the column dividers should be shown all the time, only when there's an item next to them, or when the divider is between two items.
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row-rule
Shorthand property that sets the thickness, style, and color of row separator lines, in the context of a flex container, or a grid container.
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row-rule-break
Defines how the line separator traits behave at the intersections with the column separator traits.
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row-rule-color
Defines the color of the dividing lines within a grid or flex-box container.
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row-rule-inset
Sets the spacing at the ends of the line divider lines (in a grid container or any other container that displays blocks in columns).
⚠
row-rule-style
Defines the line style to be used for separating lines, in the context of a grid container or a flex-box container.
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row-rule-visibility-items
Sets whether the line separators should be shown all the time, only when there's an item next to them, or when the line is between two items.
Row-rule-width
Defines the thickness of the line separation traits in a grid container or flex-box container context.
⚠
rule
Shorthand property that assigns the same values to the lines separating the rows and those separating the columns.
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rule-break
Property that defines how the row and column gridlines behave at their intersection.
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rule-color
Sets the color of the dividing lines between rows and columns, in the context of a grid container, a flex container, or any other container that displays blocks in rows or columns.
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rule-inset
Check if the lines separating the rows and the ones separating the columns touch at the intersections (like in a grid container or any other container that lays out blocks in rows and columns).
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rule-overlap
Define which of the lines separating the rows or the lines separating the columns go above the others.
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rule-style
Sets the style for the line between rows and columns, in the context of a grid container, a flex container, or any other container that displays blocks in rows and columns.
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rule-visibility-items
Sets whether the divider lines should be shown all the time, only when there's an item next to them, or when the line is between two items.
⚠
rule-width
Sets the thickness of the lines that separate rows and columns, in the context of a container displaying blocks in rows and columns (grid, flex-box, etc.).