05커서를 따라 기울어지는 플랜 카드

<main class="stage">
  <div class="ct is-demo">
    <div class="ct__scene" id="ct-scene">
      <div class="ct__card" id="ct-card">
        <span class="ct__name">프리미엄</span>
        <span class="ct__price">
          <span class="ct__amount">$99</span>
          <span class="ct__unit">/ 월</span>
        </span>
        <span class="ct__feat">무제한 프로젝트</span>
      </div>
    </div>
  </div>
</main>

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

$duration: $dur-base;
$easing: $ease-out;
$color: $subject-lilac;

@include stage($stage-ink);

.ct {
  box-sizing: border-box;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: $subject-cream;
}

// 3D 는 감싸는 요소가 만든다 — perspective 가 여기 없으면 rotateX/Y 가 납작한 찌그러짐으로 보인다
.ct__scene {
  perspective: 700px;
  padding: $sp-2;
}

.ct__card {
  box-sizing: border-box;
  position: relative;
  overflow: hidden;
  width: min(260px, 76vw);
  padding: $sp-5;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: $sp-2;
  border: 2px solid $color;
  border-radius: $r-card;
  background-color: rgba(255, 255, 255, .08);
  box-shadow: $shadow-raised;
  transform: rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg));
}
// 커서를 따라가는 동안은 transition 없이(한 프레임 늦게 따라오면 고무처럼 늘어져 보인다),
// 떠날 때만 .is-idle 이 붙어 스르르 눕는다
.ct__card.is-idle { transition: transform $duration $easing; }

// 글레어 — 커서와 같은 좌표(--mx·--my)를 중심으로 밝은 띠가 얹힌다. 색은 투명 흰색만
.ct__card::after {
  content: "";
  position: absolute;
  inset: -30%;
  pointer-events: none;
  background-image: radial-gradient(circle at var(--mx, 50%) var(--my, 50%),
    rgba(255, 255, 255, .38), rgba(255, 255, 255, .10) 34%, rgba(255, 255, 255, 0) 62%);
}

.ct__name {
  font-size: 12px;
  line-height: 18px;
  font-weight: 700;
  color: $color;
}
.ct__price {
  display: flex;
  align-items: baseline;
  gap: $sp-1;
}
.ct__amount {
  font-size: 30px;
  line-height: 36px;
  font-weight: 800;
}
.ct__unit {
  font-size: 12px;
  line-height: 18px;
  font-weight: 600;
  opacity: 1;
}
.ct__feat {
  font-size: 12px;
  line-height: 18px;
  font-weight: 600;
  opacity: .82;
}

// ── 자동 루프: 8자(리사주 1:2)로 천천히 돈다. 90도 근처로 가지 않으니 컷(steps) 없이 linear 로 이어 붙인다 ──
.ct.is-demo .ct__card {
  animation-name: ct-tilt;
  animation-duration: $dur-loop;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}
@keyframes ct-tilt {
  0%   { transform: rotateX(0deg) rotateY(0deg); }
  11%  { transform: rotateX(5deg) rotateY(6.4deg); }
  22%  { transform: rotateX(0deg) rotateY(9deg); }
  33%  { transform: rotateX(-5deg) rotateY(6.4deg); }
  44%  { transform: rotateX(0deg) rotateY(0deg); }
  55%  { transform: rotateX(5deg) rotateY(-6.4deg); }
  66%  { transform: rotateX(0deg) rotateY(-9deg); }
  77%  { transform: rotateX(-5deg) rotateY(-6.4deg); }
  88%  { transform: rotateX(0deg) rotateY(0deg); }
  100% { transform: rotateX(0deg) rotateY(0deg); }
}

// 글레어는 같은 시계로 같은 궤적을 돈다 — 기울기와 빛이 어긋나면 3D 로 안 읽힌다
.ct.is-demo .ct__card::after {
  animation-name: ct-glare;
  animation-duration: $dur-loop;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}
@keyframes ct-glare {
  0%   { transform: translate(0%, 0%); }
  11%  { transform: translate(18%, -14%); }
  22%  { transform: translate(26%, 0%); }
  33%  { transform: translate(18%, 14%); }
  44%  { transform: translate(0%, 0%); }
  55%  { transform: translate(-18%, -14%); }
  66%  { transform: translate(-26%, 0%); }
  77%  { transform: translate(-18%, 14%); }
  88%  { transform: translate(0%, 0%); }
  100% { transform: translate(0%, 0%); }
}

@media (max-width: 340px) {
  .ct__scene { padding: $sp-1; }
  .ct__card { padding: $sp-4; gap: $sp-1; }
  .ct__amount { font-size: 24px; line-height: 28px; }
  .ct__name { font-size: 11px; line-height: 16px; }
  .ct__unit { font-size: 11px; line-height: 16px; }
  .ct__feat { font-size: 11px; line-height: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  .ct__card.is-idle { transition: none; }
  .ct.is-demo .ct__card,
  .ct.is-demo .ct__card::after { animation: none !important; }
  .ct.is-demo .ct__card { transform: rotateX(0deg) rotateY(0deg); }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ct {
  box-sizing: border-box;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: #fff7e6;
}

.ct__scene {
  perspective: 700px;
  padding: 8px;
}

.ct__card {
  box-sizing: border-box;
  position: relative;
  overflow: hidden;
  width: min(260px, 76vw);
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  border: 2px solid #b9a0ff;
  border-radius: 16px;
  background-color: rgba(255, 255, 255, 0.08);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform: rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg));
}

.ct__card.is-idle {
  transition: transform 300ms ease-out;
}

.ct__card::after {
  content: "";
  position: absolute;
  inset: -30%;
  pointer-events: none;
  background-image: radial-gradient(circle at var(--mx, 50%) var(--my, 50%), rgba(255, 255, 255, 0.38), rgba(255, 255, 255, 0.1) 34%, rgba(255, 255, 255, 0) 62%);
}

.ct__name {
  font-size: 12px;
  line-height: 18px;
  font-weight: 700;
  color: #b9a0ff;
}

.ct__price {
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.ct__amount {
  font-size: 30px;
  line-height: 36px;
  font-weight: 800;
}

.ct__unit {
  font-size: 12px;
  line-height: 18px;
  font-weight: 600;
  opacity: 1;
}

.ct__feat {
  font-size: 12px;
  line-height: 18px;
  font-weight: 600;
  opacity: 0.82;
}

.ct.is-demo .ct__card {
  animation-name: ct-tilt;
  animation-duration: 2s;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}

@keyframes ct-tilt {
  0% {
    transform: rotateX(0deg) rotateY(0deg);
  }
  11% {
    transform: rotateX(5deg) rotateY(6.4deg);
  }
  22% {
    transform: rotateX(0deg) rotateY(9deg);
  }
  33% {
    transform: rotateX(-5deg) rotateY(6.4deg);
  }
  44% {
    transform: rotateX(0deg) rotateY(0deg);
  }
  55% {
    transform: rotateX(5deg) rotateY(-6.4deg);
  }
  66% {
    transform: rotateX(0deg) rotateY(-9deg);
  }
  77% {
    transform: rotateX(-5deg) rotateY(-6.4deg);
  }
  88% {
    transform: rotateX(0deg) rotateY(0deg);
  }
  100% {
    transform: rotateX(0deg) rotateY(0deg);
  }
}
.ct.is-demo .ct__card::after {
  animation-name: ct-glare;
  animation-duration: 2s;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}

@keyframes ct-glare {
  0% {
    transform: translate(0%, 0%);
  }
  11% {
    transform: translate(18%, -14%);
  }
  22% {
    transform: translate(26%, 0%);
  }
  33% {
    transform: translate(18%, 14%);
  }
  44% {
    transform: translate(0%, 0%);
  }
  55% {
    transform: translate(-18%, -14%);
  }
  66% {
    transform: translate(-26%, 0%);
  }
  77% {
    transform: translate(-18%, 14%);
  }
  88% {
    transform: translate(0%, 0%);
  }
  100% {
    transform: translate(0%, 0%);
  }
}
@media (max-width: 340px) {
  .ct__scene {
    padding: 4px;
  }
  .ct__card {
    padding: 16px;
    gap: 4px;
  }
  .ct__amount {
    font-size: 24px;
    line-height: 28px;
  }
  .ct__name {
    font-size: 11px;
    line-height: 16px;
  }
  .ct__unit {
    font-size: 11px;
    line-height: 16px;
  }
  .ct__feat {
    font-size: 11px;
    line-height: 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ct__card.is-idle {
    transition: none;
  }
  .ct.is-demo .ct__card,
  .ct.is-demo .ct__card::after {
    animation: none !important;
  }
  .ct.is-demo .ct__card {
    transform: rotateX(0deg) rotateY(0deg);
  }
}

// 실제 동작: pointermove 로 커서의 카드 안 상대 좌표(0~1)를 읽어 --rx·--ry(기울기)와 --mx·--my(글레어 위치)로 넣는다.
// CSS 는 그 변수만 본다 — 각도 계산은 여기, 그리기는 저쪽.
var root = document.querySelector('.ct');
var scene = document.getElementById('ct-scene');
var card = document.getElementById('ct-card');
var LIMIT = 9; // deg — 이보다 크게 기울이면 카드가 모서리에서 본 그림이 된다
function tilt(e) {
  root.classList.remove('is-demo');
  card.classList.remove('is-idle');   // 따라다니는 동안은 transition 없이 바로 붙는다
  var r = card.getBoundingClientRect();
  var x = (e.clientX - r.left) / r.width;
  var y = (e.clientY - r.top) / r.height;
  card.style.setProperty('--ry', ((x - 0.5) * 2 * LIMIT).toFixed(2) + 'deg');
  card.style.setProperty('--rx', ((0.5 - y) * 2 * LIMIT).toFixed(2) + 'deg');
  card.style.setProperty('--mx', (x * 100).toFixed(1) + '%');
  card.style.setProperty('--my', (y * 100).toFixed(1) + '%');
}
function rest() {
  card.classList.add('is-idle');      // 떠날 때만 transition 이 걸려 스르르 눕는다
  card.style.setProperty('--rx', '0deg');
  card.style.setProperty('--ry', '0deg');
  card.style.setProperty('--mx', '50%');
  card.style.setProperty('--my', '50%');
}
scene.addEventListener('pointermove', tilt);
scene.addEventListener('pointerleave', rest);

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

// React 이벤트 타입은 'react' 앰비언트에 없다 — 쓰는 모양만 여기서 직접 적는다
type PtrEvt = {
  clientX: number;
  clientY: number;
  currentTarget: { getBoundingClientRect(): { left: number; top: number; width: number; height: number } };
};

export type CardTiltProps = {
  planName?: string;
  amount?: string;
  unit?: string;
  feature?: string;
  /** 기울기 한계(deg). 이보다 크면 모서리에서 본 그림이 된다 */
  limit?: number;
  duration?: number;
  easing?: string;
  color?: string;
};

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

const REST = { rx: 0, ry: 0, mx: 50, my: 50 };

export default function CardTilt({
  planName = "Premium",
  amount = "$99",
  unit = "/ mo",
  feature = "Unlimited projects",
  limit = 9,
  duration = 300,
  easing = "ease-out",
  color = "#b9a0ff",
}: CardTiltProps) {
  const [demo, setDemo] = useState(true);
  const [idle, setIdle] = useState(false);
  const [t, setT] = useState(REST);

  // 커서의 카드 안 상대 좌표(0~1)를 각도와 글레어 위치로 옮긴다
  function move(e: PtrEvt) {
    const r = e.currentTarget.getBoundingClientRect();
    const x = (e.clientX - r.left) / r.width;
    const y = (e.clientY - r.top) / r.height;
    setDemo(false);
    setIdle(false); // 따라다니는 동안은 transition 없이 바로 붙는다
    setT({ rx: (0.5 - y) * 2 * limit, ry: (x - 0.5) * 2 * limit, mx: x * 100, my: y * 100 });
  }
  function leave() {
    setIdle(true); // 떠날 때만 transition 이 걸려 스르르 눕는다
    setT(REST);
  }

  const vars: Vars = {
    "--duration": `${duration}ms`,
    "--easing": easing,
    "--color": color,
    "--rx": `${t.rx.toFixed(2)}deg`,
    "--ry": `${t.ry.toFixed(2)}deg`,
    "--mx": `${t.mx.toFixed(1)}%`,
    "--my": `${t.my.toFixed(1)}%`,
  };

  return (
    <div className={`${styles.ct} ${demo ? styles.isDemo : ""}`} style={vars}>
      <div className={styles.scene}>
        <div
          className={`${styles.card} ${idle ? styles.isIdle : ""}`}
          onPointerMove={move}
          onPointerLeave={leave}
        >
          <span className={styles.name}>{planName}</span>
          <span className={styles.price}>
            <span className={styles.amount}>{amount}</span>
            <span className={styles.unit}>{unit}</span>
          </span>
          <span className={styles.feat}>{feature}</span>
        </div>
      </div>
    </div>
  );
}