07Link xuất hiện lần lượt

<main class="stage is-demo">
  <button class="burger" type="button" aria-label="Mở menu">
    <span class="bar bar1"></span>
    <span class="bar bar2"></span>
    <span class="bar bar3"></span>
  </button>
  <nav class="menu" aria-hidden="true">
    <a class="menu__link" href="#" style="--i:0">Trang chủ</a>
    <a class="menu__link" href="#" style="--i:1">Giới thiệu</a>
    <a class="menu__link" href="#" style="--i:2">Sản phẩm</a>
    <a class="menu__link" href="#" style="--i:3">Liên hệ</a>
  </nav>
</main>

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

// ── 변수 3개 (값은 토큰에서 받는다) ──────────────────────
$stagger: 30ms;            // 링크 사이 간격
$duration: 220ms;          // 링크 하나가 나타나는 시간
$color: $subject-cream;    // 줄·메뉴 글자 색

@include stage($stage-orange);

.stage { position: relative; }

.burger {
  position: absolute; top: clamp(14px, 5vmin, 20px); left: clamp(14px, 5vmin, 20px);
  z-index: 2; width: clamp(34px, 10vmin, 42px); height: clamp(34px, 10vmin, 42px);
  border: 0; border-radius: $r-control; background: transparent;
  padding: 0; cursor: pointer; -webkit-tap-highlight-color: transparent;
}

.bar {
  position: absolute; left: 50%; top: 50%;
  width: clamp(20px, 6.4vmin, 26px); height: 3px; border-radius: 2px;
  background: $color;
  transition: transform $dur-quick $ease-spring, opacity $dur-quick $ease-spring;
}
.bar1 { transform: translate(-50%, -50%) translateY(-7px) rotate(0deg); }
.bar2 { transform: translate(-50%, -50%) scaleX(1); opacity: 1; }
.bar3 { transform: translate(-50%, -50%) translateY(7px) rotate(0deg); }

.menu {
  position: absolute; top: clamp(52px, 16vmin, 64px); left: clamp(14px, 5vmin, 20px);
  display: grid; gap: clamp(6px, 2.2vmin, 10px);
  width: clamp(120px, 40vmin, 160px);
  padding: clamp(12px, 4vmin, 16px);
  border-radius: $r-card; background: $stage-paper; box-shadow: $shadow-raised;
  opacity: 0; pointer-events: none;
  transition: opacity $dur-instant linear;
}
.menu__link {
  font-weight: 600; font-size: clamp(11px, 3.6vmin, 13px); line-height: 1; font-family: inherit; color: $stage-ink; text-decoration: none;
  opacity: 0; transform: translateY(-6px);
  transition: opacity $duration $ease-spring, transform $duration $ease-spring;
  transition-delay: calc(var(--i) * #{$stagger});
}

.stage.is-open .bar1 { transform: translate(-50%, -50%) translateY(0) rotate(45deg); }
.stage.is-open .bar2 { transform: translate(-50%, -50%) scaleX(0); opacity: 0; }
.stage.is-open .bar3 { transform: translate(-50%, -50%) translateY(0) rotate(-45deg); }
.stage.is-open .menu { opacity: 1; pointer-events: auto; }
.stage.is-open .menu__link { opacity: 1; transform: translateY(0); }

.stage.is-demo .bar1  { animation: bar1-loop $dur-loop $ease-spring infinite; }
.stage.is-demo .bar2  { animation: bar2-loop $dur-loop $ease-spring infinite; }
.stage.is-demo .bar3  { animation: bar3-loop $dur-loop $ease-spring infinite; }
.stage.is-demo .menu  { animation: menu-loop $dur-loop linear infinite; }
.stage.is-demo .menu__link { animation: link-loop $dur-loop $ease-spring infinite; animation-delay: calc(var(--i) * #{$stagger}); }

@keyframes bar1-loop {
  0%   { transform: translate(-50%, -50%) translateY(-7px) rotate(0deg); }
  15%  { transform: translate(-50%, -50%) translateY(0) rotate(45deg); }
  70%  { transform: translate(-50%, -50%) translateY(0) rotate(45deg); }
  85%  { transform: translate(-50%, -50%) translateY(-7px) rotate(0deg); }
  100% { transform: translate(-50%, -50%) translateY(-7px) rotate(0deg); }
}
@keyframes bar2-loop {
  0%   { transform: translate(-50%, -50%) scaleX(1); opacity: 1; }
  15%  { transform: translate(-50%, -50%) scaleX(0); opacity: 0; }
  70%  { transform: translate(-50%, -50%) scaleX(0); opacity: 0; }
  85%  { transform: translate(-50%, -50%) scaleX(1); opacity: 1; }
  100% { transform: translate(-50%, -50%) scaleX(1); opacity: 1; }
}
@keyframes bar3-loop {
  0%   { transform: translate(-50%, -50%) translateY(7px) rotate(0deg); }
  15%  { transform: translate(-50%, -50%) translateY(0) rotate(-45deg); }
  70%  { transform: translate(-50%, -50%) translateY(0) rotate(-45deg); }
  85%  { transform: translate(-50%, -50%) translateY(7px) rotate(0deg); }
  100% { transform: translate(-50%, -50%) translateY(7px) rotate(0deg); }
}
@keyframes menu-loop {
  0%   { opacity: 0; }
  15%  { opacity: 1; }
  70%  { opacity: 1; }
  85%  { opacity: 0; }
  100% { opacity: 0; }
}
@keyframes link-loop {
  0%   { opacity: 0; transform: translateY(-6px); }
  20%  { opacity: 1; transform: translateY(0); }
  65%  { opacity: 1; transform: translateY(0); }
  80%  { opacity: 0; transform: translateY(-6px); }
  100% { opacity: 0; transform: translateY(-6px); }
}

// ── 접근성 ─────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .bar1, .stage.is-demo .bar2, .stage.is-demo .bar3,
  .stage.is-demo .menu, .stage.is-demo .menu__link { animation: none; }
  .bar, .menu, .menu__link { transition-duration: 1ms; transition-delay: 0ms; }
}

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;
}

.burger {
  position: absolute;
  top: clamp(14px, 5vmin, 20px);
  left: clamp(14px, 5vmin, 20px);
  z-index: 2;
  width: clamp(34px, 10vmin, 42px);
  height: clamp(34px, 10vmin, 42px);
  border: 0;
  border-radius: 12px;
  background: transparent;
  padding: 0;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.bar {
  position: absolute;
  left: 50%;
  top: 50%;
  width: clamp(20px, 6.4vmin, 26px);
  height: 3px;
  border-radius: 2px;
  background: #fff7e6;
  transition: transform 220ms cubic-bezier(0.2, 0.8, 0.2, 1), opacity 220ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.bar1 {
  transform: translate(-50%, -50%) translateY(-7px) rotate(0deg);
}

.bar2 {
  transform: translate(-50%, -50%) scaleX(1);
  opacity: 1;
}

.bar3 {
  transform: translate(-50%, -50%) translateY(7px) rotate(0deg);
}

.menu {
  position: absolute;
  top: clamp(52px, 16vmin, 64px);
  left: clamp(14px, 5vmin, 20px);
  display: grid;
  gap: clamp(6px, 2.2vmin, 10px);
  width: clamp(120px, 40vmin, 160px);
  padding: clamp(12px, 4vmin, 16px);
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  opacity: 0;
  pointer-events: none;
  transition: opacity 140ms linear;
}

.menu__link {
  font-weight: 600;
  font-size: clamp(11px, 3.6vmin, 13px);
  line-height: 1;
  font-family: inherit;
  color: #17141a;
  text-decoration: none;
  opacity: 0;
  transform: translateY(-6px);
  transition: opacity 220ms cubic-bezier(0.2, 0.8, 0.2, 1), transform 220ms cubic-bezier(0.2, 0.8, 0.2, 1);
  transition-delay: calc(var(--i) * 30ms);
}

.stage.is-open .bar1 {
  transform: translate(-50%, -50%) translateY(0) rotate(45deg);
}

.stage.is-open .bar2 {
  transform: translate(-50%, -50%) scaleX(0);
  opacity: 0;
}

.stage.is-open .bar3 {
  transform: translate(-50%, -50%) translateY(0) rotate(-45deg);
}

.stage.is-open .menu {
  opacity: 1;
  pointer-events: auto;
}

.stage.is-open .menu__link {
  opacity: 1;
  transform: translateY(0);
}

.stage.is-demo .bar1 {
  animation: bar1-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.stage.is-demo .bar2 {
  animation: bar2-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.stage.is-demo .bar3 {
  animation: bar3-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.stage.is-demo .menu {
  animation: menu-loop 2s linear infinite;
}

.stage.is-demo .menu__link {
  animation: link-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
  animation-delay: calc(var(--i) * 30ms);
}

@keyframes bar1-loop {
  0% {
    transform: translate(-50%, -50%) translateY(-7px) rotate(0deg);
  }
  15% {
    transform: translate(-50%, -50%) translateY(0) rotate(45deg);
  }
  70% {
    transform: translate(-50%, -50%) translateY(0) rotate(45deg);
  }
  85% {
    transform: translate(-50%, -50%) translateY(-7px) rotate(0deg);
  }
  100% {
    transform: translate(-50%, -50%) translateY(-7px) rotate(0deg);
  }
}
@keyframes bar2-loop {
  0% {
    transform: translate(-50%, -50%) scaleX(1);
    opacity: 1;
  }
  15% {
    transform: translate(-50%, -50%) scaleX(0);
    opacity: 0;
  }
  70% {
    transform: translate(-50%, -50%) scaleX(0);
    opacity: 0;
  }
  85% {
    transform: translate(-50%, -50%) scaleX(1);
    opacity: 1;
  }
  100% {
    transform: translate(-50%, -50%) scaleX(1);
    opacity: 1;
  }
}
@keyframes bar3-loop {
  0% {
    transform: translate(-50%, -50%) translateY(7px) rotate(0deg);
  }
  15% {
    transform: translate(-50%, -50%) translateY(0) rotate(-45deg);
  }
  70% {
    transform: translate(-50%, -50%) translateY(0) rotate(-45deg);
  }
  85% {
    transform: translate(-50%, -50%) translateY(7px) rotate(0deg);
  }
  100% {
    transform: translate(-50%, -50%) translateY(7px) rotate(0deg);
  }
}
@keyframes menu-loop {
  0% {
    opacity: 0;
  }
  15% {
    opacity: 1;
  }
  70% {
    opacity: 1;
  }
  85% {
    opacity: 0;
  }
  100% {
    opacity: 0;
  }
}
@keyframes link-loop {
  0% {
    opacity: 0;
    transform: translateY(-6px);
  }
  20% {
    opacity: 1;
    transform: translateY(0);
  }
  65% {
    opacity: 1;
    transform: translateY(0);
  }
  80% {
    opacity: 0;
    transform: translateY(-6px);
  }
  100% {
    opacity: 0;
    transform: translateY(-6px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .bar1, .stage.is-demo .bar2, .stage.is-demo .bar3,
  .stage.is-demo .menu, .stage.is-demo .menu__link {
    animation: none;
  }
  .bar, .menu, .menu__link {
    transition-duration: 1ms;
    transition-delay: 0ms;
  }
}

(function () {
  var stage = document.querySelector('.stage');
  var burger = document.querySelector('.burger');
  var open = false;
  burger.addEventListener('click', function () {
    stage.classList.remove('is-demo');
    open = !open;
    stage.classList.toggle('is-open', open);
    burger.setAttribute('aria-label', open ? 'Đóng menu' : 'Mở menu');
  });
})();

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

export type StaggerLinksProps = {
  links: string[];
  openLabel: string;
  closeLabel: string;
  /** 링크 사이 간격 (기본 30ms) */
  stagger?: number;
  /** 링크 하나가 나타나는 시간 (기본 220ms) */
  duration?: number;
  color?: string;
};

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

export default function StaggerLinks({
  links,
  openLabel,
  closeLabel,
  stagger = 30,
  duration = 220,
  color = "#fff7e6",
}: StaggerLinksProps) {
  const [open, setOpen] = useState(false);
  const vars: Vars = { "--duration": `${duration}ms`, "--color": color };
  const cls = (base: string) => (open ? `${base} ${styles.isOpen}` : base);

  return (
    <div className={styles.stage} style={vars}>
      <button
        type="button"
        className={cls(styles.burger)}
        aria-label={open ? closeLabel : openLabel}
        onClick={() => setOpen((v) => !v)}
      >
        <span className={`${styles.bar} ${styles.bar1}`} />
        <span className={`${styles.bar} ${styles.bar2}`} />
        <span className={`${styles.bar} ${styles.bar3}`} />
      </button>
      <nav className={cls(styles.menu)} aria-hidden={!open}>
        {links.map((label, i) => {
          const linkVars: LinkVars = { "--delay": `${i * stagger}ms` };
          return (
            <a key={label} className={styles.menuLink} style={linkVars} href="#">
              {label}
            </a>
          );
        })}
      </nav>
    </div>
  );
}