`scroll-margin-block-start` CSS property

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.

Try it

scroll-margin-block-start: 0;

scroll-margin-block-start: 20px;

scroll-margin-block-start: 2em;

<section class="default-example" id="default-example">
  <div class="scroller">
    <div>1</div>
    <div id="example-element">2</div>
    <div>3</div>
  </div>
  <div class="info">Scroll »</div>
</section>

.default-example .info {
  inline-size: 100%;
  padding: 0.5em 0;
  font-size: 90%;
  writing-mode: vertical-rl;
}

.scroller {
  text-align: left;
  height: 250px;
  width: 270px;
  overflow-y: scroll;
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  border: 1px solid black;
  scroll-snap-type: y mandatory;
}

.scroller > div {
  flex: 0 0 250px;
  background-color: rebeccapurple;
  color: white;
  font-size: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  scroll-snap-align: start;
}

.scroller > div:nth-child(even) {
  background-color: white;
  color: rebeccapurple;
}

Syntax

/* <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: revert;
scroll-margin-block-start: revert-layer;
scroll-margin-block-start: unset;

Values

<length>

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

Formal definition

Formal syntax

scroll-margin-block-start = 
  <length>

Specifications

Browser compatibility

See also

• CSS scroll snap module
• Well-controlled scrolling with CSS scroll snap on web.dev (2018)