07Mở trễ (transition-delay)

<main class="stage">
  <nav class="menu is-demo">
    <button class="menu__trigger" type="button" aria-expanded="false">Sản phẩm</button>
    <ul class="menu__panel">
      <li><a href="#">Tính năng</a></li>
      <li><a href="#">Bảng giá</a></li>
      <li><a href="#">Khách hàng</a></li>
    </ul>
  </nav>
</main>

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

$duration: $dur-quick;                             // 열리고 닫히는 시간
$easing: $ease-out;                                // 시작 빠르고 끝은 부드럽게
$delay: 150ms;                                     // 진입 후 기다리는 시간 (닫힐 땐 지연 없음)
$color: $subject-cream;                            // 트리거 버튼 색 (주황 무대와 대비)

@include stage($stage-orange);

.menu {
  position: relative;
  align-self: flex-start;                            // 패널이 트리거 아래로 열려 무대 중앙에 두면 아래로 넘친다 — 위로 붙여 여유를 둔다 (실측 320px 재검증 2026-09-10)
  font-weight: 500;
  font-size: clamp(13px, 3.6vw, 16px);
  line-height: 1.4;
  font-family: inherit;

  &__trigger {
    border: 0;
    border-radius: $r-control;
    padding: clamp(9px, 3vw, 13px) clamp(16px, 4vw, 22px);
    font-weight: 700;
    font-family: inherit;
    color: $stage-ink;
    background: $color;
    cursor: pointer;
  }

  &__panel {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    width: max-content;
    max-width: min(150px, 76vw);
    margin: 0;
    padding: 6px;
    list-style: none;
    background: $subject-cream;
    border-radius: $r-card;
    box-shadow: $shadow-raised;
    opacity: 0;
    transform: translateY(-6px);
    pointer-events: none;
    transition: opacity $duration $easing, transform $duration $easing;  // 닫힐 때는 지연 없이 바로
  }

  &__panel li a {
    display: block;
    padding: 8px 12px;
    border-radius: $r-control - 4px;
    color: $stage-ink;
    text-decoration: none;
  }
  &__panel li a:hover { background: rgba($stage-ink, .06); }

  // 마우스가 지나가기만 해선 안 열리게 — 진입 후 $delay 를 기다렸다가 연다
  &:hover &__panel,
  &.is-open &__panel {
    opacity: 1;
    transform: none;
    pointer-events: auto;
    transition-delay: $delay;
  }

  &.is-demo &__panel { animation: reveal-loop $dur-loop $easing infinite; }
}

@keyframes reveal-loop {
  0%, 40%   { opacity: 0; transform: translateY(-6px); }
  55%, 80%  { opacity: 1; transform: none; }
  95%, 100% { opacity: 0; transform: translateY(-6px); }
}

@media (prefers-reduced-motion: reduce) {
  .menu__panel { transition: none !important; }
  .menu.is-demo .menu__panel { animation: none; opacity: 0; transform: none; }
}

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);
}

.menu {
  position: relative;
  align-self: flex-start;
  font-weight: 500;
  font-size: clamp(13px, 3.6vw, 16px);
  line-height: 1.4;
  font-family: inherit;
}
.menu__trigger {
  border: 0;
  border-radius: 12px;
  padding: clamp(9px, 3vw, 13px) clamp(16px, 4vw, 22px);
  font-weight: 700;
  font-family: inherit;
  color: #17141a;
  background: #fff7e6;
  cursor: pointer;
}
.menu__panel {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  width: max-content;
  max-width: min(150px, 76vw);
  margin: 0;
  padding: 6px;
  list-style: none;
  background: #fff7e6;
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  opacity: 0;
  transform: translateY(-6px);
  pointer-events: none;
  transition: opacity 220ms ease-out, transform 220ms ease-out;
}
.menu__panel li a {
  display: block;
  padding: 8px 12px;
  border-radius: 8px;
  color: #17141a;
  text-decoration: none;
}
.menu__panel li a:hover {
  background: rgba(23, 20, 26, 0.06);
}
.menu:hover .menu__panel, .menu.is-open .menu__panel {
  opacity: 1;
  transform: none;
  pointer-events: auto;
  transition-delay: 150ms;
}
.menu.is-demo .menu__panel {
  animation: reveal-loop 2s ease-out infinite;
}

@keyframes reveal-loop {
  0%, 40% {
    opacity: 0;
    transform: translateY(-6px);
  }
  55%, 80% {
    opacity: 1;
    transform: none;
  }
  95%, 100% {
    opacity: 0;
    transform: translateY(-6px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .menu__panel {
    transition: none !important;
  }
  .menu.is-demo .menu__panel {
    animation: none;
    opacity: 0;
    transform: none;
  }
}

// 데스크톱은 :hover + transition-delay 로만 연다(아래 CSS). 터치 화면을 위해 클릭 토글도 둔다.
var m = document.querySelector('.menu'), t = m.querySelector('.menu__trigger');
t.addEventListener('click', function () {
  m.classList.remove('is-demo');
  t.setAttribute('aria-expanded', m.classList.toggle('is-open'));
});

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

export type HoverIntentDropdownProps = {
  triggerLabel: string;
  items: string[];
  /** 열리고 닫히는 시간 (기본 220ms) */
  duration?: number;
  easing?: string;
  /** 진입 후 기다리는 시간 (기본 150ms, 닫힐 땐 지연 없음) */
  delay?: number;
  color?: string;
};

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

export default function HoverIntentDropdown({
  triggerLabel,
  items,
  duration = 220,
  easing = "ease-out",
  delay = 150,
  color = "#fff7e6",
}: HoverIntentDropdownProps) {
  const [open, setOpen] = useState(false);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--delay": `${delay}ms`, "--color": color };

  return (
    // 데스크톱은 CSS :hover 만으로 지연 열림이 동작한다. 터치 화면을 위해 클릭 토글도 겸한다.
    <nav className={styles.menu} style={vars} onClick={() => setOpen((v) => !v)}>
      <button type="button" className={styles.trigger} aria-expanded={open}>{triggerLabel}</button>
      <ul className={open ? `${styles.panel} ${styles.panelOpen}` : styles.panel}>
        {items.map((label) => (
          <li key={label}><a href="#">{label}</a></li>
        ))}
      </ul>
    </nav>
  );
}