Scroll Area

Apply the scrollArea patch to any block element to replace the default browser scrollbar with a thin, themed overlay scrollbar. Sets overflow: auto and styles ::-webkit-scrollbar pseudo-elements (Chrome/Safari/Edge) and scrollbar-width/scrollbar-color (Firefox).

Props

Prop	Type	Default	Description
`color`	`ValueOrState<ThemeColor>`	`"neutral"`	Theme color for the scrollbar thumb.

Example

import { scrollArea } from "@domphy/ui";

const List = {
  div: [...longContent],
  $: [scrollArea()],
  style: { maxHeight: "300px" },
};

Customization

Must see the source of patch at the bottom of each patch page to understand the structure then code it still code as html native element.

There are four levels of customization, in increasing order of effort:

Patch props. Each patch exposes a small, stable set of props—typically fewer than five. Lowest friction.
Context attributes. Use dataTone, dataSize, and dataDensity on a container to shift tone, size, or density for an entire subtree without touching individual elements.
Inline override. Native-wins merge strategy: any property set directly on the element overrides the patch value.
Create a variant. Clone a similar patch and edit it. Use this only when you need a reusable custom version.

Formulas

Unit - U = fontSize / 4 - convert final values with themeSpacing(n).

Size - n = intrinsic text lines, w = wrapping level, d = density factor:

height        = (n * 6 + 2 * d * w) * U
paddingBlock  = d * w * U
paddingInline = ceil(3 / w) * d * w * U
radius        = d * w * U

Base density d = 1.5:

U	w=0	w=1	w=2	w=3
height (`n = 1`)	6	9	12	15
paddingBlock	0	1.5	3	4.5
paddingInline	3	4.5	6	4.5
radius	0	1.5	3	4.5

Tone - K = N / 2 where N is the palette length. For N = 18, K = 9.

Role	Shift	n=0
Background	parent +/- n	0
Text	bg + K	6
Border	bg + K/2	3
Hover	bg + 2K/3	4
Selected / Focus	above +/- K/3	2-4

State shift range: K/3 <= delta <= 2K/3.

scrollArea

import type { PartialElement, StyleObject } from "@domphy/core";
import { toState, type ValueOrState } from "@domphy/core";
import { type ThemeColor, themeColor, themeSpacing } from "@domphy/theme";

/**
 * Applies thin, themed overlay scrollbars to any scrollable container.
 * Covers WebKit (Chrome/Safari/Edge) via `::-webkit-scrollbar` pseudo-elements
 * and Firefox via `scrollbar-width`/`scrollbar-color`. Sets `overflow: auto`.
 * No host-tag check; apply to any block element.
 *
 * @param props.color - Theme color for the scrollbar thumb. Accepts a value or
 *   reactive state. Defaults to `"neutral"`.
 * @example { div: [...], style: { maxHeight: "300px" }, $: [scrollArea()] }
 */
function scrollArea(
  props: { color?: ValueOrState<ThemeColor> } = {},
): PartialElement {
  const color = toState(props.color ?? "neutral", "color");

  return {
    style: {
      overflow: "auto",
      "&::-webkit-scrollbar": {
        width: themeSpacing(2),
        height: themeSpacing(2),
      },
      "&::-webkit-scrollbar-track": {
        background: "transparent",
      },
      "&::-webkit-scrollbar-thumb": {
        backgroundColor: (l) => themeColor(l, "shift-5", color.get(l)),
        borderRadius: themeSpacing(999),
        // Transparent border creates visual padding around the thumb.
        border: `${themeSpacing(0.5)} solid transparent`,
        backgroundClip: "content-box",
      },
      "&::-webkit-scrollbar-thumb:hover": {
        backgroundColor: (l) => themeColor(l, "shift-7", color.get(l)),
      },
      // Firefox thin scrollbar with matching thumb/track colors.
      scrollbarWidth: "thin",
      scrollbarColor: (l) =>
        `${themeColor(l, "shift-5", color.get(l))} transparent`,
    } as StyleObject,
  };
}

export { scrollArea };

Scroll Area#

Props#

Example#

Scroll Area

Props

Example