08Checkbox nảy khi chạm

<main class="stage">
  <label class="cb">
    <input type="checkbox" class="cb__input">
    <span class="cb__box is-demo" aria-hidden="true">
      <svg class="cb__check" viewBox="0 0 24 24"><path d="M4 12l6 6L20 6"/></svg>
    </span>
    <span class="cb__label">Tôi đồng ý với điều khoản</span>
  </label>
</main>

@use "../../../../site/static/demo-tokens" as *;

$duration: $dur-quick;                            // 박스가 튀고 체크가 그려지는 시간
$easing: $ease-pop;
$color: $subject-blue;                            // 체크됐을 때 색

@include stage($stage-paper);

.cb {
  min-height: 44px;                               // 시각적 박스는 26px 이지만, 탭 영역(label 전체)은 44px 이상
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.cb__input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}
.cb__box {
  position: relative;
  width: 26px;
  height: 26px;
  border-radius: 6px;
  border: 2px solid rgba($stage-ink, .3);
  background: $subject-cream;
  display: grid;
  place-items: center;
  transform: scale(1);
  transition: transform $duration $easing, border-color $duration $easing, background $duration $easing;

  // 규칙8 한 겹: 체크되는 순간 박스 바깥으로 두 겹 링이 불규칙하게 번지다 감쇠
  &::after {
    content: "";
    position: absolute;
    inset: -2px;
    border-radius: inherit;
    box-shadow: 0 0 0 0 rgba($color, .45), 0 0 0 0 rgba($color, .26);
    opacity: 0;
    pointer-events: none;
  }
}
.cb__check {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: $subject-cream;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 24;
  stroke-dashoffset: 24;
  transition: stroke-dashoffset $duration $easing;
}
.cb__label { font-weight: 600; font-size: 13px; line-height: 1.3; font-family: inherit; color: $stage-ink; }

.cb__input:checked ~ .cb__box {
  border-color: $color;
  background: $color;
  transform: scale(1.08);
}
.cb__input:checked ~ .cb__box::after {
  animation: ripple-wave $dur-enter $easing;
}
.cb__input:checked ~ .cb__box .cb__check { stroke-dashoffset: 0; }
.cb__input:focus-visible ~ .cb__box {
  outline: 3px solid $subject-blue;
  outline-offset: 2px;
}

// 데모용: 실제 체크 상태와 무관하게 박스와 체크를 함께 반복 재생한다
.cb__box.is-demo { animation: check-loop $dur-loop $easing infinite; }
.cb__box.is-demo::after { animation: ripple-loop $dur-loop $easing infinite; }
.cb__box.is-demo .cb__check { animation: draw-loop $dur-loop $easing infinite; }

@keyframes check-loop {
  0%, 20%  { transform: scale(1);    border-color: rgba($stage-ink, .3); background: $subject-cream; }
  35%      { transform: scale(1.08); border-color: $color;               background: $color; }
  55%,100% { transform: scale(1);    border-color: $color;               background: $color; }
}
@keyframes draw-loop {
  0%, 20%  { stroke-dashoffset: 24; }
  45%,100% { stroke-dashoffset: 0; }
}

@keyframes ripple-wave {
  0%   { box-shadow: 0 0 0 0 rgba($color, .72), 0 0 0 0 rgba($color, .52); opacity: 1; }
  14%  { box-shadow: 0 0 0 6px rgba($color, .72), 0 0 0 2px rgba($color, .52); opacity: 1; }
  44%  { box-shadow: 0 0 0 9px rgba($color, .62), 0 0 0 5px rgba($color, .46); opacity: 1; }
  52%  { box-shadow: 0 0 0 10px rgba($color, 0), 0 0 0 6px rgba($color, 0); opacity: 0; }
  100% { box-shadow: 0 0 0 10px rgba($color, 0), 0 0 0 6px rgba($color, 0); opacity: 0; }
}

@keyframes ripple-loop {
  0%, 20%   { box-shadow: 0 0 0 0 rgba($color, .72), 0 0 0 0 rgba($color, .52); opacity: 1; }
  25%       { box-shadow: 0 0 0 6px rgba($color, .72), 0 0 0 2px rgba($color, .52); opacity: 1; }
  44%       { box-shadow: 0 0 0 9px rgba($color, .62), 0 0 0 5px rgba($color, .46); opacity: 1; }
  52%       { box-shadow: 0 0 0 10px rgba($color, 0), 0 0 0 6px rgba($color, 0); opacity: 0; }
  58%, 100% { box-shadow: 0 0 0 10px rgba($color, 0), 0 0 0 6px rgba($color, 0); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .cb__box, .cb__check { transition: none; }
  .cb__box::after { animation: none !important; opacity: 0; }
  .cb__box.is-demo, .cb__box.is-demo .cb__check { animation: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cb {
  min-height: 44px;
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.cb__input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}

.cb__box {
  position: relative;
  width: 26px;
  height: 26px;
  border-radius: 6px;
  border: 2px solid rgba(23, 20, 26, 0.3);
  background: #fff7e6;
  display: grid;
  place-items: center;
  transform: scale(1);
  transition: transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1), border-color 220ms cubic-bezier(0.2, 1.4, 0.4, 1), background 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}
.cb__box::after {
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: inherit;
  box-shadow: 0 0 0 0 rgba(47, 109, 246, 0.45), 0 0 0 0 rgba(47, 109, 246, 0.26);
  opacity: 0;
  pointer-events: none;
}

.cb__check {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: #fff7e6;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 24;
  stroke-dashoffset: 24;
  transition: stroke-dashoffset 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.cb__label {
  font-weight: 600;
  font-size: 13px;
  line-height: 1.3;
  font-family: inherit;
  color: #17141a;
}

.cb__input:checked ~ .cb__box {
  border-color: #2f6df6;
  background: #2f6df6;
  transform: scale(1.08);
}

.cb__input:checked ~ .cb__box::after {
  animation: ripple-wave 600ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.cb__input:checked ~ .cb__box .cb__check {
  stroke-dashoffset: 0;
}

.cb__input:focus-visible ~ .cb__box {
  outline: 3px solid #2f6df6;
  outline-offset: 2px;
}

.cb__box.is-demo {
  animation: check-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.cb__box.is-demo::after {
  animation: ripple-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.cb__box.is-demo .cb__check {
  animation: draw-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes check-loop {
  0%, 20% {
    transform: scale(1);
    border-color: rgba(23, 20, 26, 0.3);
    background: #fff7e6;
  }
  35% {
    transform: scale(1.08);
    border-color: #2f6df6;
    background: #2f6df6;
  }
  55%, 100% {
    transform: scale(1);
    border-color: #2f6df6;
    background: #2f6df6;
  }
}
@keyframes draw-loop {
  0%, 20% {
    stroke-dashoffset: 24;
  }
  45%, 100% {
    stroke-dashoffset: 0;
  }
}
@keyframes ripple-wave {
  0% {
    box-shadow: 0 0 0 0 rgba(47, 109, 246, 0.72), 0 0 0 0 rgba(47, 109, 246, 0.52);
    opacity: 1;
  }
  14% {
    box-shadow: 0 0 0 6px rgba(47, 109, 246, 0.72), 0 0 0 2px rgba(47, 109, 246, 0.52);
    opacity: 1;
  }
  44% {
    box-shadow: 0 0 0 9px rgba(47, 109, 246, 0.62), 0 0 0 5px rgba(47, 109, 246, 0.46);
    opacity: 1;
  }
  52% {
    box-shadow: 0 0 0 10px rgba(47, 109, 246, 0), 0 0 0 6px rgba(47, 109, 246, 0);
    opacity: 0;
  }
  100% {
    box-shadow: 0 0 0 10px rgba(47, 109, 246, 0), 0 0 0 6px rgba(47, 109, 246, 0);
    opacity: 0;
  }
}
@keyframes ripple-loop {
  0%, 20% {
    box-shadow: 0 0 0 0 rgba(47, 109, 246, 0.72), 0 0 0 0 rgba(47, 109, 246, 0.52);
    opacity: 1;
  }
  25% {
    box-shadow: 0 0 0 6px rgba(47, 109, 246, 0.72), 0 0 0 2px rgba(47, 109, 246, 0.52);
    opacity: 1;
  }
  44% {
    box-shadow: 0 0 0 9px rgba(47, 109, 246, 0.62), 0 0 0 5px rgba(47, 109, 246, 0.46);
    opacity: 1;
  }
  52% {
    box-shadow: 0 0 0 10px rgba(47, 109, 246, 0), 0 0 0 6px rgba(47, 109, 246, 0);
    opacity: 0;
  }
  58%, 100% {
    box-shadow: 0 0 0 10px rgba(47, 109, 246, 0), 0 0 0 6px rgba(47, 109, 246, 0);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cb__box, .cb__check {
    transition: none;
  }
  .cb__box::after {
    animation: none !important;
    opacity: 0;
  }
  .cb__box.is-demo, .cb__box.is-demo .cb__check {
    animation: none;
  }
}

import { useState, type CSSProperties, type ChangeEvent } from "react";
import styles from "./TapCheckbox.module.scss";

export type TapCheckboxProps = {
  label: string;
  /** 같은 페이지에 여러 개 둘 때 겹치지 않게 */
  id?: string;
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };

export default function TapCheckbox({
  label,
  id = "tap-checkbox",
  duration = 220,
  easing = "cubic-bezier(.2,1.4,.4,1)",
  color = "#2f6df6",
}: TapCheckboxProps) {
  const [checked, setChecked] = useState(false);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <label className={styles.cb} style={vars} htmlFor={id}>
      <input
        id={id}
        type="checkbox"
        className={styles.input}
        checked={checked}
        onChange={(e: ChangeEvent<HTMLInputElement>) => setChecked(e.target.checked)}
      />
      <span className={styles.box} aria-hidden="true">
        <svg className={styles.check} viewBox="0 0 24 24"><path d="M4 12l6 6L20 6" /></svg>
      </span>
      <span className={styles.label}>{label}</span>
    </label>
  );
}