07Icon morph transition

<main class="stage">
  <div class="panel">
    <p class="panel__title">Toolbar</p>
    <p class="panel__line"></p>
    <span class="icon">
      <span class="icon__core icon__core--sun"></span>
      <span class="icon__core icon__core--moon"></span>
      <span class="icon__ray" style="--i:0"></span>
      <span class="icon__ray" style="--i:1"></span>
      <span class="icon__ray" style="--i:2"></span>
      <span class="icon__ray" style="--i:3"></span>
      <span class="icon__ray" style="--i:4"></span>
      <span class="icon__ray" style="--i:5"></span>
    </span>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────
$duration: $dur-quick;
$easing: $ease-pop;
$color: $stage-yellow;

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

.panel {
  position: relative; overflow: hidden;
  width: clamp(200px, 70vw, 260px); height: clamp(120px, 42vw, 150px);
  border-radius: $r-card; box-shadow: $shadow-raised;
  background: $subject-cream; color: $subject-ink;
  box-sizing: border-box; padding: clamp(12px, 5vw, 18px); text-align: left;
}
.panel__title { margin: 0 0 6px; font-weight: 700; font-size: clamp(12px, 3.6vw, 15px); line-height: 1.3; font-family: inherit; }
.panel__line { margin: 0; width: 55%; height: 8px; border-radius: 4px; background: currentColor; opacity: .25; }

// 광선이 접혀 사라지고 원 안에 크레이터가 떠오른다. transform: scale·rotate 와 opacity 만 쓴다.
.icon {
  position: absolute; top: clamp(10px, 4vw, 16px); right: clamp(10px, 4vw, 16px);
  width: 34px; height: 34px;
}
.icon__core { position: absolute; inset: 6px; border-radius: 50%; }
.icon__core--sun  { background: $color; opacity: 1; animation: core-light $dur-loop $easing infinite; }
.icon__core--moon { background: $stage-ink; opacity: 0; animation: core-dark $dur-loop $easing infinite; }
.icon__ray {
  position: absolute; top: 50%; left: 50%; width: 3px; height: 8px; border-radius: 2px;
  background: $color; transform-origin: 50% 17px; // 규칙8: 아이콘 중심 회전축
  transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  animation: ray-fold $dur-loop $easing infinite;
}

@keyframes core-light { 0%, 15% { opacity: 1; } 40%, 60% { opacity: 0; } 85%, 100% { opacity: 1; } }
@keyframes core-dark  { 0%, 15% { opacity: 0; } 40%, 60% { opacity: 1; } 85%, 100% { opacity: 0; } }
@keyframes ray-fold {
  0%, 15% { opacity: 1; transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1); }
  40%, 60% { opacity: 0; transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(0); }
  85%, 100% { opacity: 1; transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1); }
}

// ── 접근성: 움직임 줄이기 설정이면 태양 상태로 고정 ──────────
@media (prefers-reduced-motion: reduce) {
  .icon__core--sun, .icon__core--moon, .icon__ray { animation: none !important; }
}

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);
}

.panel {
  position: relative;
  overflow: hidden;
  width: clamp(200px, 70vw, 260px);
  height: clamp(120px, 42vw, 150px);
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: #fff7e6;
  color: #17141a;
  box-sizing: border-box;
  padding: clamp(12px, 5vw, 18px);
  text-align: left;
}

.panel__title {
  margin: 0 0 6px;
  font-weight: 700;
  font-size: clamp(12px, 3.6vw, 15px);
  line-height: 1.3;
  font-family: inherit;
}

.panel__line {
  margin: 0;
  width: 55%;
  height: 8px;
  border-radius: 4px;
  background: currentColor;
  opacity: 0.25;
}

.icon {
  position: absolute;
  top: clamp(10px, 4vw, 16px);
  right: clamp(10px, 4vw, 16px);
  width: 34px;
  height: 34px;
}

.icon__core {
  position: absolute;
  inset: 6px;
  border-radius: 50%;
}

.icon__core--sun {
  background: #ffd23f;
  opacity: 1;
  animation: core-light 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.icon__core--moon {
  background: #17141a;
  opacity: 0;
  animation: core-dark 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.icon__ray {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 3px;
  height: 8px;
  border-radius: 2px;
  background: #ffd23f;
  transform-origin: 50% 17px;
  transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  animation: ray-fold 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes core-light {
  0%, 15% {
    opacity: 1;
  }
  40%, 60% {
    opacity: 0;
  }
  85%, 100% {
    opacity: 1;
  }
}
@keyframes core-dark {
  0%, 15% {
    opacity: 0;
  }
  40%, 60% {
    opacity: 1;
  }
  85%, 100% {
    opacity: 0;
  }
}
@keyframes ray-fold {
  0%, 15% {
    opacity: 1;
    transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  }
  40%, 60% {
    opacity: 0;
    transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(0);
  }
  85%, 100% {
    opacity: 1;
    transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  }
}
@media (prefers-reduced-motion: reduce) {
  .icon__core--sun, .icon__core--moon, .icon__ray {
    animation: none !important;
  }
}

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

export type IconMorphToggleProps = {
  dark: boolean;
  onToggle?: () => void;
  /** 광선이 접히는 시간 (기본 220ms) */
  duration?: number;
  easing?: string;
  color?: string;
  className?: string;
};

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

const RAYS = [0, 1, 2, 3, 4, 5];

export default function IconMorphToggle({
  dark,
  onToggle,
  duration = 220,
  easing = "cubic-bezier(.2,1.4,.4,1)",
  color = "#ffd23f",
  className = "",
}: IconMorphToggleProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <button
      type="button"
      className={`${styles.icon} ${className}`}
      style={vars}
      data-dark={dark}
      aria-label="다크모드 전환"
      onClick={onToggle}
    >
      <span className={`${styles.core} ${styles.coreLight}`} />
      <span className={`${styles.core} ${styles.coreDark}`} />
      {RAYS.map((i) => {
        const rayVars: RayVars = { "--i": i };
        return <span key={i} className={styles.ray} style={rayVars} />;
      })}
    </button>
  );
}