The scroll-margin-block-start property defines the margin of the scroll snap area at the start of the block dimension that is used for snapping this box to the snapport. The scroll snap area is determined by taking the transformed border box, finding its rectangular bounding box (axis-aligned in the scroll container’s coordinate space), then adding the specified outsets.


/* <length> values */
scroll-margin-block-start: 10px;
scroll-margin-block-start: 1em;

/* Global values */
scroll-margin-block-start: inherit;
scroll-margin-block-start: initial;
scroll-margin-block-start: unset;


An outset from the block start edge of the scroll container.

Formal definition

Initial value 0
Applies to all elements
Inherited no
Computed value as specified
Animation type by computed value type

Formal syntax



Specification Status Comment
CSS Scroll Snap Module Level 1
The definition of 'scroll-margin-block-start' in that specification.
Candidate Recommendation Initial definition

Browser compatibilityUpdate compatibility data on GitHub

Chrome Edge Firefox Internet Explorer Opera Safari
scroll-margin-block-start 69 79 68 No 56 No
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
scroll-margin-block-start 69 69 68 48 No 10.0

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