Input Checkbox

Use the input-checkbox patch to customize this element.

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.

inputCheckbox

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

/**
 * Styles a custom checkbox with themed box, check mark, indeterminate state,
 * hover, focus and disabled styling. Apply to an `<input>` element of
 * type `checkbox` (the patch sets `type: "checkbox"`).
 *
 * @hostTag input
 * @param props.color - Optional theme color tone for the box/border (`ValueOrState<ThemeColor>`). Defaults to `"neutral"`.
 * @param props.accentColor - Optional theme color tone for the checked/indeterminate fill and focus ring (`ValueOrState<ThemeColor>`). Defaults to `"primary"`.
 * @example { input: null, type: "checkbox", $: [inputCheckbox()] }
 */
function inputCheckbox(
  props: {
    color?: ValueOrState<ThemeColor>;
    accentColor?: ValueOrState<ThemeColor>;
  } = {},
): PartialElement {
  const color = toState(props.color ?? "neutral", "color");
  const accentColor = toState(props.accentColor ?? "primary", "accentColor");

  return {
    type: "checkbox",
    _onInsert: (node) => {
      if (node.tagName !== "input") {
        console.warn(`"inputCheckbox" primitive patch must use input tag`);
      }
    },
    style: {
      appearance: "none",
      fontSize: (listener) => themeSize(listener, "inherit"),
      display: "inline-flex",
      position: "relative",
      width: themeSpacing(6),
      height: themeSpacing(6),
      justifyContent: "center",
      alignItems: "center",
      transition: "background-color 300ms, outline-color 300ms",
      margin: 0,
      padding: 0,
      "&::before": {
        content: `""`,
        display: "block",
        borderRadius: themeSpacing(1),
        lineHeight: 1,
        cursor: "pointer",
        border: "none",
        outlineOffset: "-1px",
        outline: (listener) =>
          `1px solid ${themeColor(listener, "shift-4", color.get(listener))}`,
        color: (listener) =>
          themeColor(listener, "shift-9", color.get(listener)),
        width: themeSpacing(4),
        height: themeSpacing(4),
      },
      "&:hover::before": {
        backgroundColor: (listener) =>
          themeColor(listener, "shift-2", color.get(listener)),
      },
      "&:checked::before": {
        outline: (listener) =>
          `1px solid ${themeColor(listener, "shift-6", accentColor.get(listener))}`,
        backgroundColor: (listener) =>
          themeColor(listener, "shift-8", accentColor.get(listener)),
      },
      "&:checked:hover:not([disabled])::before": {
        backgroundColor: (listener) =>
          themeColor(listener, "shift-7", accentColor.get(listener)),
      },
      "&:checked::after": {
        content: `""`,
        display: "block",
        position: "absolute",
        top: "25%",
        insetInlineStart: "37%",
        width: "20%",
        height: "30%",
        border: (listener) =>
          `${themeSpacing(0.5)} solid ${themeColor(listener, "inherit", accentColor.get(listener))}`,
        borderTop: 0,
        borderInlineStart: 0,
        transform: "rotate(45deg)",
      },
      "&:indeterminate::before": {
        outline: (listener) =>
          `1px solid ${themeColor(listener, "shift-6", accentColor.get(listener))}`,
        backgroundColor: (listener) =>
          themeColor(listener, "shift-3", accentColor.get(listener)),
      },
      "&:indeterminate::after": {
        content: `""`,
        position: "absolute",
        inset: "30%",
        backgroundColor: (listener) =>
          themeColor(listener, "shift-8", accentColor.get(listener)),
      },
      "&:indeterminate:hover:not([disabled])::after": {
        backgroundColor: (listener) =>
          themeColor(listener, "shift-7", accentColor.get(listener)),
      },
      "&:focus-visible": {
        borderRadius: themeSpacing(1.5),
        outline: (listener) =>
          `${themeSpacing(0.5)} solid ${themeColor(listener, "shift-6", accentColor.get(listener))}`,
      },
      "&[disabled]": {
        cursor: "not-allowed",
      },
      "&[disabled]::before, &[disabled]::after": {
        outline: "none",
        backgroundColor: (listener) =>
          themeColor(listener, "shift-4", "neutral"),
        pointerEvents: "none",
      },
    },
  };
}

export { inputCheckbox };

</div>