07motion-safeガード

<main class="stage">
  <button class="btn is-demo" type="button">変更を保存</button>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: 220ms;
$easing: cubic-bezier(.2, .8, .2, 1);
$color: $subject-cream;

// ── 데모 무대 ──────────────────────────────────────────
@include stage($stage-orange);

.btn {
  border: 0;
  border-radius: $r-control;
  padding: $sp-4 $sp-8;
  font-weight: 700;
  font-size: clamp(15px, 4vw, 17px);
  line-height: 1;
  font-family: inherit;
  color: $subject-ink;
  background: $color;
  cursor: pointer;
  box-shadow: $shadow-press;
}

// 실사용: motion-safe: 에서만 뜨고, motion-reduce: 는 그림자만 옅게
@media (prefers-reduced-motion: no-preference) {
  .btn {
    transition: transform $duration $easing, box-shadow $duration $easing;
    &:hover, &:focus-visible { transform: translateY(-4px); box-shadow: $shadow-raised; }
    &:active { transform: translateY(-1px); }
  }
}
@media (prefers-reduced-motion: reduce) {
  .btn { transition: box-shadow $duration linear; }
  .btn:hover, .btn:focus-visible { box-shadow: $shadow-raised; }
}

// 데모: 호버를 강제로 2초마다 반복 — reduced-motion 이 아닐 때만
.btn.is-demo {
  @media (prefers-reduced-motion: no-preference) {
    animation: lift-loop 2s $easing infinite;
  }
}

@keyframes lift-loop {
  0%, 25%   { transform: translateY(0);    box-shadow: $shadow-press; }
  50%       { transform: translateY(-4px); box-shadow: $shadow-raised; }
  75%, 100% { transform: translateY(0);    box-shadow: $shadow-press; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.btn {
  border: 0;
  border-radius: 12px;
  padding: 16px 32px;
  font-weight: 700;
  font-size: clamp(15px, 4vw, 17px);
  line-height: 1;
  font-family: inherit;
  color: #17141a;
  background: #fff7e6;
  cursor: pointer;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

@media (prefers-reduced-motion: no-preference) {
  .btn {
    transition: transform 220ms cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 220ms cubic-bezier(0.2, 0.8, 0.2, 1);
  }
  .btn:hover, .btn:focus-visible {
    transform: translateY(-4px);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  .btn:active {
    transform: translateY(-1px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .btn {
    transition: box-shadow 220ms linear;
  }
  .btn:hover, .btn:focus-visible {
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
}
@media (prefers-reduced-motion: no-preference) {
  .btn.is-demo {
    animation: lift-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
  }
}

@keyframes lift-loop {
  0%, 25% {
    transform: translateY(0);
    box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  }
  50% {
    transform: translateY(-4px);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  75%, 100% {
    transform: translateY(0);
    box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  }
}

import type { CSSProperties } from "react";
import styles from "./MotionSafeButton.module.scss";

export type MotionSafeButtonProps = {
  label?: string;
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function MotionSafeButton({
  label = "Save changes",
  duration = 220,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#fff7e6",
}: MotionSafeButtonProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <button type="button" className={styles.btn} style={vars}>
      {label}
    </button>
  );
}