# scroll-padding

> Applies logical `scroll-padding` so a scroll snap position or anchor jump lands clear of a sticky header — set it to the header's height.

```ts
import { scrollPadding } from "@sdxc/u/overflow";
```

Applies logical `scroll-padding` so a scroll snap position or anchor jump
lands clear of a sticky header — set it to the header's height. Follows
`p()`'s 1/2/4-value logical mapping; see [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_logical_properties_and_values).

## Quick reference

Every documented call, beside the CSS it emits.

| Call | CSS |
| --- | --- |
| `u.scrollPadding(4)` | `css({ scrollPadding: "calc(var(--ui-spacing, 0.25rem) * 4)" })` |
| `u.scrollPadding(16, 0)` | `css({ scrollPaddingBlock: "...", scrollPaddingInline: "..." })` |

## Examples

### Basic example

Use `scrollPadding(n)` on a scroll container to keep anchor jumps and snap positions clear of a sticky header. Click a link and the section stops below the header:

```tsx
<div mix={[vstack({ gap: 4 }), is(72), maxIs("100%")]}>
	<nav mix={[hstack({ gap: 3 })]}>
		<a href="#padded-1">Section 1</a>
		<a href="#padded-2">Section 2</a>
		<a href="#padded-3">Section 3</a>
	</nav>
	<div
		mix={[
			scroll("y"),
			scrollPadding(14),
			vstack({ gap: 3 }),
			bs(56),
			pi(4),
			pbe(4),
			...,
		]}
	>
		<header mix={[sticky(), insBs(0), bg(), p(3), ...]}>Sticky header</header>
		<section id="padded-1" mix={[shrink(), bs(32), ...]}>
			Section 1
		</section>
		<section id="padded-2" mix={[shrink(), bs(32), ...]}>
			Section 2
		</section>
		<section id="padded-3" mix={[shrink(), bs(32), ...]}>
			Section 3
		</section>
	</div>
</div>
```

### Insetting snap positions

Pass a block and an inline value, like `scrollPadding(0, 8)`, to inset where items snap along a carousel. Scroll the row and each card settles away from the edge:

```tsx
<div
	mix={[
		scroll("x"),
		scrollSnapType(),
		scrollPadding(0, 8),
		hstack({ gap: 4 }),
		is(96),
		maxIs("100%"),
		p(4),
		...,
	]}
>
	<div mix={[scrollSnapAlign(), shrink(), is(56), bs(32), ...]}>1</div>
	<div mix={[scrollSnapAlign(), shrink(), is(56), bs(32), ...]}>2</div>
	<div mix={[scrollSnapAlign(), shrink(), is(56), bs(32), ...]}>3</div>
	<div mix={[scrollSnapAlign(), shrink(), is(56), bs(32), ...]}>4</div>
</div>
```

## Using a custom value

Every scale argument also takes a raw CSS value, which passes through untouched.

```ts
u.scrollPadding("2.75rem")
```

## Applying on a state

Wrap the call in a state utility to scope it to one selector.

```ts
u.hover(u.scrollPadding(4))
```

## Responsive design

Wrap the call in a container query to scope it to one width.

```ts
u.at("md", u.scrollPadding(4))
```

## Customizing your theme

### Customizing spacing

Every numeric step multiplies `--ui-spacing`, so redefining it rescales every spacing and sizing utility at once:

```css
:root {
	--ui-spacing: 0.25rem;
}
```

Every call that names the step now reads the new value:

```ts
scrollPadding(4)
```

## Signature

```ts
u.scrollPadding(...values: SpacingValue[])
```