09모바일 전체 시트

<main class="stage">
  <button class="menu__trigger is-demo" type="button" aria-expanded="false">메뉴</button>
  <ul class="menu__sheet">
    <li><a href="#">홈</a></li>
    <li><a href="#">검색</a></li>
    <li><a href="#">마이페이지</a></li>
    <li><a href="#">설정</a></li>
  </ul>
</main>

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

$duration: $dur-base;                              // 시트가 올라오는 시간
$easing: $ease-out;                                // 시작 빠르고 끝은 부드럽게
$color: $subject-blue-deep;                        // 트리거 버튼 색 (크림 글자가 얹히므로 진한 파랑)

@include stage($stage-ink);

.stage { position: relative; overflow: hidden; }     // 시트의 기준 — 닫힌 시트는 translateY(100%) 로 화면 아래에 있다.
                                                      // 열렸을 땐 시트가 무대 안에 완전히 들어오므로(위 계산: top 112 / bottom 300, 무대는 0~300) 잘리지 않는다.
                                                      // overflow:hidden 이 없으면 닫힌 상태의 화면 밖 188px 가 body.scrollHeight 를 밀어 올려 320px 재검증에서 넘침으로 잡힌다

.menu__trigger {
  border: 0;
  border-radius: $r-control;
  padding: clamp(9px, 3vw, 13px) clamp(16px, 4vw, 22px);
  font-weight: 700;
  font-size: clamp(13px, 3.6vw, 16px);
  line-height: 1;
  font-family: inherit;
  color: $subject-cream;
  background: $color;
  cursor: pointer;
}

.menu__sheet {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0;
  padding: 10px 10px calc(10px + env(safe-area-inset-bottom, 0px));
  list-style: none;
  background: $subject-cream;
  border-radius: $r-card $r-card 0 0;
  box-shadow: $shadow-raised;
  transform: translateY(100%);                      // 화면 아래에서 전체 폭으로 올라온다
}

.menu__sheet li a {
  display: block;
  padding: clamp(9px, 2.6vw, 12px) 12px;
  border-radius: $r-control - 4px;
  color: $stage-ink;
  text-decoration: none;
  text-align: center;
  font-weight: 600;
  font-size: clamp(13px, 3.6vw, 15px);
  line-height: 1.2;
  font-family: inherit;
}
.menu__sheet li a:hover { background: rgba($stage-ink, .06); }

.menu__sheet.is-open { transform: translateY(0); transition: transform $duration $easing; }

.menu__trigger.is-demo ~ .menu__sheet { animation: sheet-loop $dur-loop $easing infinite; }

@keyframes sheet-loop {
  0%, 30%   { transform: translateY(100%); }
  45%, 80%  { transform: translateY(0); }
  95%, 100% { transform: translateY(100%); }
}

@media (prefers-reduced-motion: reduce) {
  .menu__sheet { transition: none !important; }
  .menu__trigger.is-demo ~ .menu__sheet { animation: none; transform: translateY(100%); }
}

// 320px 에서도 넘치지 않게 — 좁은 화면일수록 오히려 이 패턴이 맞는 크기다
@media (max-width: 360px) {
  .menu__sheet { padding-bottom: calc(8px + env(safe-area-inset-bottom, 0px)); }
}

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;
}

.menu__trigger {
  border: 0;
  border-radius: 12px;
  padding: clamp(9px, 3vw, 13px) clamp(16px, 4vw, 22px);
  font-weight: 700;
  font-size: clamp(13px, 3.6vw, 16px);
  line-height: 1;
  font-family: inherit;
  color: #fff7e6;
  background: #0a4fe8;
  cursor: pointer;
}

.menu__sheet {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0;
  padding: 10px 10px calc(10px + env(safe-area-inset-bottom, 0px));
  list-style: none;
  background: #fff7e6;
  border-radius: 16px 16px 0 0;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform: translateY(100%);
}

.menu__sheet li a {
  display: block;
  padding: clamp(9px, 2.6vw, 12px) 12px;
  border-radius: 8px;
  color: #17141a;
  text-decoration: none;
  text-align: center;
  font-weight: 600;
  font-size: clamp(13px, 3.6vw, 15px);
  line-height: 1.2;
  font-family: inherit;
}

.menu__sheet li a:hover {
  background: rgba(23, 20, 26, 0.06);
}

.menu__sheet.is-open {
  transform: translateY(0);
  transition: transform 300ms ease-out;
}

.menu__trigger.is-demo ~ .menu__sheet {
  animation: sheet-loop 2s ease-out infinite;
}

@keyframes sheet-loop {
  0%, 30% {
    transform: translateY(100%);
  }
  45%, 80% {
    transform: translateY(0);
  }
  95%, 100% {
    transform: translateY(100%);
  }
}
@media (prefers-reduced-motion: reduce) {
  .menu__sheet {
    transition: none !important;
  }
  .menu__trigger.is-demo ~ .menu__sheet {
    animation: none;
    transform: translateY(100%);
  }
}
@media (max-width: 360px) {
  .menu__sheet {
    padding-bottom: calc(8px + env(safe-area-inset-bottom, 0px));
  }
}

// 트리거를 클릭하면 열리고, 시트 바깥을 클릭하면 닫힌다. 데모(.is-demo)는 스스로 반복한다.
var t = document.querySelector('.menu__trigger'), s = document.querySelector('.menu__sheet');
t.addEventListener('click', function () {
  t.classList.remove('is-demo');
  t.setAttribute('aria-expanded', s.classList.toggle('is-open'));
});
document.addEventListener('pointerdown', function (e) {
  if (s.classList.contains('is-open') && !s.contains(e.target) && e.target !== t) { s.classList.remove('is-open'); t.setAttribute('aria-expanded', false); }
});

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

export type MobileFullSheetDropdownProps = {
  triggerLabel: string;
  items: string[];
  /** 시트가 올라오는 시간 (기본 300ms) */
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function MobileFullSheetDropdown({
  triggerLabel,
  items,
  duration = 300,
  easing = "ease-out",
  color = "#0a4fe8",
}: MobileFullSheetDropdownProps) {
  const [open, setOpen] = useState(false);
  const ref = useRef<HTMLDivElement>(null);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  useEffect(() => {
    function onDown(e: PointerEvent) {
      if (ref.current && !ref.current.contains(e.target as Node)) setOpen(false);
    }
    document.addEventListener("pointerdown", onDown);
    return () => document.removeEventListener("pointerdown", onDown);
  }, []);

  return (
    <div className={styles.stage} ref={ref} style={vars}>
      <button type="button" className={styles.trigger} aria-expanded={open} onClick={() => setOpen((v) => !v)}>
        {triggerLabel}
      </button>
      <ul className={open ? `${styles.sheet} ${styles.sheetOpen}` : styles.sheet}>
        {items.map((label) => (
          <li key={label}><a href="#">{label}</a></li>
        ))}
      </ul>
    </div>
  );
}