03Overlay mờ dần

<main class="stage is-demo">
  <div class="page" id="page">
    <button class="trigger" type="button" aria-haspopup="dialog" aria-controls="drawer3">Mở bộ lọc</button>
  </div>
  <div class="overlay"></div>
  <div class="drawer" id="drawer3" role="dialog" aria-modal="true" aria-labelledby="t3">
    <h2 id="t3">Bộ lọc</h2>
    <p>Chọn giá, vận chuyển và màu sắc ở đây.</p>
    <button class="drawer__close" type="button">Đóng</button>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-base;       // 300ms — 자리에서 나타나는 시간
$easing: $ease-out;
$color: $subject-cream;     // 트리거 강조색

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

.stage { position: relative; }
.page { display: grid; place-items: center; }

.trigger {
  border: 0; border-radius: $r-pill;
  padding: $sp-3 $sp-6;
  font-weight: 600;
  font-size: clamp(13px, 4vmin, 16px);
  line-height: 1;
  font-family: inherit;
  color: $subject-orange-deep; background: $color;   // AA: 크림 면 위 주황 글자 5.04:1
  cursor: pointer; -webkit-tap-highlight-color: transparent;
}

// 프로스트 유리 느낌: opacity + backdrop-filter 로 흐려진다(01 의 단색 어둡기와 다르다)
.overlay {
  position: fixed; inset: 0;
  background: rgba($stage-ink, .28);
  backdrop-filter: blur(0px);
  opacity: 0; pointer-events: none;
  transition: opacity $duration $easing, backdrop-filter $duration $easing;
}

// 패널은 왼쪽에서 움직이지 않는다 — opacity·transform:scale 만으로 나타난다
.drawer {
  position: fixed; left: 0; top: 0; bottom: 0; right: auto;
  transform: scale(.96);
  transform-origin: left center; // 규칙8: 왼쪽 붙은 패널 좌변 기준
  opacity: 0;
  width: min(76vw, 240px);
  box-sizing: border-box;
  display: flex; flex-direction: column; gap: $sp-2;
  padding: $sp-6 $sp-4;
  background: $stage-paper; color: $stage-ink;
  box-shadow: $shadow-raised;
  pointer-events: none;
  transition: transform $duration $easing, opacity $duration $easing;

  h2 { margin: 0 0 $sp-2; font-size: clamp(13px, 4.2vmin, 17px); }
  p  { margin: 0 0 $sp-4; font-size: clamp(10px, 3.2vmin, 13px); color: rgba($stage-ink, .7); }
}

.drawer__close {
  margin-top: auto;
  border: 0; border-radius: $r-control;
  background: $stage-orange; color: $stage-paper;
  padding: $sp-2 $sp-4;
  font-weight: 600; font-size: 13px; line-height: 1; font-family: inherit; cursor: pointer;
}

.stage.is-open .overlay { opacity: 1; backdrop-filter: blur(6px); pointer-events: auto; }
.stage.is-open .drawer  { opacity: 1; transform: scale(1); pointer-events: auto; }

.stage.is-demo .overlay { animation: overlay-loop $dur-loop ease-in-out infinite; }
.stage.is-demo .drawer  { animation: drawer-loop $dur-loop $easing infinite; }

@keyframes overlay-loop {
  0%, 100% { opacity: 0; backdrop-filter: blur(0px); }
  15%, 70% { opacity: 1; backdrop-filter: blur(6px); }
  85%      { opacity: 0; backdrop-filter: blur(0px); }
}
@keyframes drawer-loop {
  0%, 100% { opacity: 0; transform: scale(.96); }
  15%, 70% { opacity: 1; transform: scale(1); }
  85%      { opacity: 0; transform: scale(.96); }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .overlay, .stage.is-demo .drawer { animation: none; }
  .overlay, .drawer { transition-duration: 1ms; }
}

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);
}

.stage {
  position: relative;
}

.page {
  display: grid;
  place-items: center;
}

.trigger {
  border: 0;
  border-radius: 999px;
  padding: 12px 24px;
  font-weight: 600;
  font-size: clamp(13px, 4vmin, 16px);
  line-height: 1;
  font-family: inherit;
  color: #c93000;
  background: #fff7e6;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(23, 20, 26, 0.28);
  backdrop-filter: blur(0px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 300ms ease-out, backdrop-filter 300ms ease-out;
}

.drawer {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  right: auto;
  transform: scale(0.96);
  transform-origin: left center;
  opacity: 0;
  width: min(76vw, 240px);
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 24px 16px;
  background: #ffffff;
  color: #17141a;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  pointer-events: none;
  transition: transform 300ms ease-out, opacity 300ms ease-out;
}
.drawer h2 {
  margin: 0 0 8px;
  font-size: clamp(13px, 4.2vmin, 17px);
}
.drawer p {
  margin: 0 0 16px;
  font-size: clamp(10px, 3.2vmin, 13px);
  color: rgba(23, 20, 26, 0.7);
}

.drawer__close {
  margin-top: auto;
  border: 0;
  border-radius: 12px;
  background: #ff4d1f;
  color: #ffffff;
  padding: 8px 16px;
  font-weight: 600;
  font-size: 13px;
  line-height: 1;
  font-family: inherit;
  cursor: pointer;
}

.stage.is-open .overlay {
  opacity: 1;
  backdrop-filter: blur(6px);
  pointer-events: auto;
}

.stage.is-open .drawer {
  opacity: 1;
  transform: scale(1);
  pointer-events: auto;
}

.stage.is-demo .overlay {
  animation: overlay-loop 2s ease-in-out infinite;
}

.stage.is-demo .drawer {
  animation: drawer-loop 2s ease-out infinite;
}

@keyframes overlay-loop {
  0%, 100% {
    opacity: 0;
    backdrop-filter: blur(0px);
  }
  15%, 70% {
    opacity: 1;
    backdrop-filter: blur(6px);
  }
  85% {
    opacity: 0;
    backdrop-filter: blur(0px);
  }
}
@keyframes drawer-loop {
  0%, 100% {
    opacity: 0;
    transform: scale(0.96);
  }
  15%, 70% {
    opacity: 1;
    transform: scale(1);
  }
  85% {
    opacity: 0;
    transform: scale(0.96);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .overlay, .stage.is-demo .drawer {
    animation: none;
  }
  .overlay, .drawer {
    transition-duration: 1ms;
  }
}

// 패널은 이동하지 않고 자리에서 opacity·scale 로만 나타난다. 열림 시 #page 를 inert 로 막는다.
(function () {
  var stage = document.querySelector('.stage');
  var page = document.getElementById('page');
  var trigger = document.querySelector('.trigger');
  var overlay = document.querySelector('.overlay');
  var panel = document.querySelector('.drawer');
  var closeBtn = document.querySelector('.drawer__close');
  function focusables() { return panel.querySelectorAll('a, button'); }
  function open() {
    stage.classList.remove('is-demo'); stage.classList.add('is-open');
    page.setAttribute('inert', ''); page.setAttribute('aria-hidden', 'true');
    focusables()[0].focus({ preventScroll: true });
  }
  function shut() {
    stage.classList.remove('is-open');
    page.removeAttribute('inert'); page.removeAttribute('aria-hidden');
    trigger.focus({ preventScroll: true });
  }
  trigger.addEventListener('click', open);
  overlay.addEventListener('click', shut);
  closeBtn.addEventListener('click', shut);
  document.addEventListener('keydown', function (e) {
    if (!stage.classList.contains('is-open')) return;
    if (e.key === 'Escape') { shut(); return; }
    if (e.key !== 'Tab') return;
    var f = focusables(), first = f[0], last = f[f.length - 1];
    if (e.shiftKey && document.activeElement === first) { last.focus({ preventScroll: true }); e.preventDefault(); }
    else if (!e.shiftKey && document.activeElement === last) { first.focus({ preventScroll: true }); e.preventDefault(); }
  });
})();

import { useEffect, useRef, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./OverlayFadeDrawer.module.scss";

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

export default function OverlayFadeDrawer({
  duration = 300,
  easing = "ease-out",
  color = "#fff7e6",
}: OverlayFadeDrawerProps) {
  const [open, setOpen] = useState(false);
  const panelRef = useRef<HTMLDivElement | null>(null);
  const triggerRef = useRef<HTMLButtonElement | null>(null);

  useEffect(() => {
    if (!open) { triggerRef.current?.focus({ preventScroll: true }); return; }
    const panel = panelRef.current;
    if (!panel) return;
    const focusables = () => Array.from(panel.querySelectorAll<HTMLElement>("a, button"));
    focusables()[0]?.focus({ preventScroll: true });
    function onKey(e: KeyboardEvent) {
      if (e.key === "Escape") { setOpen(false); return; }
      if (e.key !== "Tab") return;
      const f = focusables();
      const first = f[0], last = f[f.length - 1];
      if (e.shiftKey && document.activeElement === first) { last.focus({ preventScroll: true }); e.preventDefault(); }
      else if (!e.shiftKey && document.activeElement === last) { first.focus({ preventScroll: true }); e.preventDefault(); }
    }
    document.addEventListener("keydown", onKey);
    return () => document.removeEventListener("keydown", onKey);
  }, [open]);

  const vars: CSSProperties = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <div className={styles.stage} style={vars}>
      <div className={styles.page} inert={open || undefined} aria-hidden={open}>
        <button ref={triggerRef} className={styles.trigger} type="button" onClick={() => setOpen(true)}>
          필터 열기
        </button>
      </div>
      <div className={styles.overlay} data-open={open} onClick={() => setOpen(false)} />
      <div ref={panelRef} className={styles.drawer} data-open={open} role="dialog" aria-modal="true" aria-label="필터">
        <h2>필터</h2>
        <p>가격·배송·색상 옵션을 여기서 고른다.</p>
        <button className={styles.close} type="button" onClick={() => setOpen(false)}>닫기</button>
      </div>
    </div>
  );
}