01Panel slide toggle — a basic panel interpolating position from an open state

<main class="stage" id="stage">
  <button class="trigger" id="trigger" type="button" aria-expanded="false" aria-controls="panel">
    Open filters
  </button>
  <aside class="panel is-demo" id="panel" aria-hidden="true">
    <p class="panel__title">Filter</p>
    <div class="panel__row">
      <span class="chip">Color</span>
      <span class="chip">Size</span>
    </div>
    <div class="panel__row">
      <span class="chip">Price range</span>
      <span class="chip">Material</span>
    </div>
  </aside>
</main>

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

$duration: $dur-enter;
$easing: $ease-spring;
$color: $subject-cream;

@include stage($stage-ink);

.stage {
  position: relative;
  overflow: hidden;
}

.trigger {
  border: 0;
  border-radius: $r-pill;
  padding: $sp-3 $sp-6;
  font-family: inherit;
  font-weight: 600;
  font-size: clamp(13px, 4vmin, 16px);
  line-height: 1;
  color: $stage-ink;
  background: $color;
  cursor: pointer;
}

.panel {
  box-sizing: border-box;
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: min(64vw, 200px);
  padding: $sp-6 $sp-4;
  display: flex;
  flex-direction: column;
  gap: $sp-3;
  background: $color;
  color: $stage-ink;
  box-shadow: $shadow-raised;
  transform: translateX(-100%);
  transition: transform $duration $easing;
}

.panel__title {
  margin: 0;
  font-weight: 600;
  font-size: 14px;
  line-height: 1.2;
}

.panel__row {
  display: flex;
  gap: $sp-2;
  flex-wrap: wrap;
}

.chip {
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba($stage-ink, .1);
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
}

.stage.is-open .panel {
  transform: translateX(0);
}

.panel.is-demo {
  animation-name: panel-loop;
  animation-duration: $dur-loop;
  animation-timing-function: $easing;
  animation-iteration-count: infinite;
}

@keyframes panel-loop {
  0%, 100% { transform: translateX(-100%); }
  18%, 72% { transform: translateX(0); }
  90% { transform: translateX(-100%); }
}

@media (max-width: 340px) {
  .panel { width: 78vw; padding: $sp-4 $sp-3; gap: $sp-2; }
  .trigger { padding: $sp-2 $sp-4; }
}

@media (prefers-reduced-motion: reduce) {
  .panel { transition: none; }
  .panel.is-demo { animation: none; transform: translateX(0); opacity: .96; }
}

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);
}

.stage {
  position: relative;
  overflow: hidden;
}

.trigger {
  border: 0;
  border-radius: 999px;
  padding: 12px 24px;
  font-family: inherit;
  font-weight: 600;
  font-size: clamp(13px, 4vmin, 16px);
  line-height: 1;
  color: #17141a;
  background: #fff7e6;
  cursor: pointer;
}

.panel {
  box-sizing: border-box;
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: min(64vw, 200px);
  padding: 24px 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  background: #fff7e6;
  color: #17141a;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform: translateX(-100%);
  transition: transform 600ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.panel__title {
  margin: 0;
  font-weight: 600;
  font-size: 14px;
  line-height: 1.2;
}

.panel__row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.chip {
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.1);
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
}

.stage.is-open .panel {
  transform: translateX(0);
}

.panel.is-demo {
  animation-name: panel-loop;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite;
}

@keyframes panel-loop {
  0%, 100% {
    transform: translateX(-100%);
  }
  18%, 72% {
    transform: translateX(0);
  }
  90% {
    transform: translateX(-100%);
  }
}
@media (max-width: 340px) {
  .panel {
    width: 78vw;
    padding: 16px 12px;
    gap: 8px;
  }
  .trigger {
    padding: 8px 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .panel {
    transition: none;
  }
  .panel.is-demo {
    animation: none;
    transform: translateX(0);
    opacity: 0.96;
  }
}

// Filter 패널 열림·닫힘을 하나의 불(boolean) 값으로만 들고, 그 값을 transform 위치(0 또는 -100%)로 바꿔 CSS transition 이 보간한다.
// 계산 겹: 열림 여부 → translateX 보간(transition). 실사용 클릭 리스너 있음.
(function () {
  var stage = document.getElementById('stage');
  var trigger = document.getElementById('trigger');
  var panel = document.getElementById('panel');
  if (!stage || !trigger || !panel) return;

  function setOpen(open) {
    stage.classList.toggle('is-open', open);
    trigger.setAttribute('aria-expanded', String(open));
    panel.setAttribute('aria-hidden', String(!open));
  }

  trigger.addEventListener('click', function () {
    panel.classList.remove('is-demo');
    setOpen(!stage.classList.contains('is-open'));
  });
})();

import { useEffect, useRef } from "react";
import styles from "./PanelSlideToggle.module.scss";

// 필터 패널 열림닫힘을 하나의 불(boolean) 값으로만 들고, 그 값을 transform 위치(0 또는 -100%)로 바꿔 CSS transition 이 보간한다.
// 계산 겹: 열림 여부 -> translateX 보간(transition). 실사용 클릭 리스너 있음.
export default function PanelSlideToggle() {
  const stageRef = useRef<HTMLElement>(null);
  const triggerRef = useRef<HTMLButtonElement>(null);
  const panelRef = useRef<HTMLElement>(null);

  useEffect(() => {
    const stage = stageRef.current;
    const trigger = triggerRef.current;
    const panel = panelRef.current;
    if (!stage || !trigger || !panel) return;

    function setOpen(open: boolean) {
      stage!.classList.toggle(styles["is-open"], open);
      trigger!.setAttribute("aria-expanded", String(open));
      panel!.setAttribute("aria-hidden", String(!open));
    }

    function onClick() {
      panel!.classList.remove(styles["is-demo"]);
      setOpen(!stage!.classList.contains(styles["is-open"]));
    }

    trigger.addEventListener("click", onClick);
    return () => {
      trigger.removeEventListener("click", onClick);
    };
  }, []);

  return (
    <main ref={stageRef} className={styles.stage}>
      <button
        ref={triggerRef}
        className={styles.trigger}
        type="button"
        aria-expanded="false"
        aria-controls="panel"
      >
        필터 열기
      </button>
      <aside ref={panelRef} className={`${styles.panel} ${styles["is-demo"]}`} aria-hidden="true">
        <p className={styles.panel__title}>필터</p>
        <div className={styles.panel__row}>
          <span className={styles.chip}>색상</span>
          <span className={styles.chip}>사이즈</span>
        </div>
        <div className={styles.panel__row}>
          <span className={styles.chip}>가격대</span>
          <span className={styles.chip}>소재</span>
        </div>
      </aside>
    </main>
  );
}