04검색 바 흡수

<main class="stage">
  <div class="sbm is-demo">
    <div class="sbm__slot">
      <header class="sbm__head">
        <span class="sbm__logo">GODRICH</span>
        <nav class="sbm__nav" aria-hidden="true"><span></span><span></span></nav>
      </header>
      <div class="sbm__search">
        <span class="sbm__search-box">
          <span class="sbm__search-icon" aria-hidden="true"></span>
          <span class="sbm__search-text">검색어를 입력하세요</span>
        </span>
      </div>
    </div>
    <div class="sbm__page">
      <p class="sbm__line"></p>
      <p class="sbm__line short"></p>
    </div>
  </div>
</main>

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

// ── 변수 3개. 변형은 이것만 바꾼다 ──────────────────────────
$duration: $dur-base;                              // 검색 줄이 위로 합쳐지는 시간
// 관성 lerp — p += (목표-p) * .32 를 20스텝 반복한 계산 결과를 커브로 굽는다 (형태 2차, 사용자 2026-09-14)
$easing: linear(0, .32, .538, .686, .786, .855, .901, .933, .954, .969, .979, .986, .99, .993, .995, .997, .998, .999, .999, .999, 1);
$easing-content: linear(0, .18, .328, .449, .548, .629, .696, .751, .796, .832, .863, .887, .908, .924, .938, .949, .958, .966, .972, .977, 1);   // 알파 .18 — 헤더보다 느리게 따라잡아 시차가 생긴다
$dur-content: $dur-base * 1.4;
$color: $subject-blue;                              // 검색 아이콘·포커스 색

@include stage($stage-paper);

$row1: 56px;
$row2: 40px;

.sbm { width: min(380px, 90vw); }

// ── 고정 높이 슬롯: 헤더 줄 + 검색 줄 두 층을 겹쳐 두고 transform 만 움직인다 ──
.sbm__slot {
  position: relative;
  height: $row1 + $row2;
}
.sbm__head {
  position: absolute; inset: 0 0 auto 0;
  z-index: 2;
  height: $row1;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 $sp-4;
}
.sbm__logo { color: $stage-ink; font-weight: 800; font-size: clamp(14px, 4vw, 18px); line-height: 1; font-family: inherit; letter-spacing: .04em; }
.sbm__nav {
  display: flex; gap: $sp-2;
  transition: opacity $duration $easing, transform $duration $easing;
  span { width: 20px; height: 6px; border-radius: $r-pill; background: rgba($stage-ink, .2); }
}
// 검색 줄은 헤더의 nav 자리(오른쪽)와 같은 정렬로 둔다 — 위로 합쳐져도 로고와 겹치지 않는다
.sbm__search {
  position: absolute; left: 0; right: 0; top: $row1;
  z-index: 1;
  height: $row2;
  display: flex; align-items: center; justify-content: flex-end;
  padding: 0 $sp-4;
  border-top: 1px solid rgba($stage-ink, .08);
  transform: translateY(0);
  transition: transform $duration $easing;

  &-box {
    display: flex; align-items: center; gap: $sp-2;
    padding: $sp-1 $sp-3;
    border-radius: $r-pill;
    background: rgba($color, .1);
  }
  &-icon { flex: none; width: 14px; height: 14px; border-radius: 50%; border: 2px solid $color; }
  &-text { font-weight: 500; font-size: clamp(11px, 3vw, 12px); line-height: 1; font-family: inherit; color: rgba($stage-ink, .72); }
}

// 실제 사용: 스크롤을 시작하면 검색 줄이 위로 미끄러져 헤더 줄 안으로 합쳐진다
.sbm.is-scrolled {
  .sbm__nav { opacity: 0; transform: translateX($sp-2); }
  .sbm__search { transform: translateY(-#{$row1}); }
  // 콘텐츠는 헤더 합쳐짐보다 늦게 도착 — 시차 스크롤
  .sbm__page { transform: translateY(-8px); }
}

// ── 데모(.is-demo): 합쳐졌다 돌아오는 2초 루프 ──────────────
.sbm.is-demo {
  .sbm__nav { animation: sbm-nav-loop $dur-loop $easing infinite; }
  .sbm__search { animation: sbm-search-loop $dur-loop $easing infinite; }
  .sbm__page { animation: sbm-page-loop $dur-loop $easing-content infinite; }
}
@keyframes sbm-nav-loop {
  0%, 20%   { opacity: 1; transform: translateX(0); }
  45%, 70%  { opacity: 0; transform: translateX(8px); }
  95%, 100% { opacity: 1; transform: translateX(0); }
}
@keyframes sbm-search-loop {
  0%, 20%   { transform: translateY(0); }
  45%, 70%  { transform: translateY(-#{$row1}); }
  95%, 100% { transform: translateY(0); }
}
// 헤더보다 느린 $easing-content 로 같은 구간을 밟는다 — 관성이 덜 붙어 뒤처져 보인다
@keyframes sbm-page-loop {
  0%, 20%   { transform: translateY(0); }
  45%, 70%  { transform: translateY(-8px); }
  95%, 100% { transform: translateY(0); }
}

// ── 배경: 문서처럼 보이는 자리 ─────────────────────────
.sbm__page {
  padding: $sp-4 0 0;
  transform: translateY(0);
  transition: transform $dur-content $easing-content;
}
.sbm__line {
  height: 10px;
  margin: 0 0 $sp-3;
  border-radius: $r-xs;
  background: rgba($stage-ink, .08);
  &.short { width: 55%; }
}

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .sbm__nav, .sbm__search, .sbm__page { transition: none; }
  .sbm.is-demo {
    .sbm__nav, .sbm__search, .sbm__page { animation: none !important; }
    .sbm__nav { opacity: 1; transform: translateX(0); }
    .sbm__search { transform: translateY(0); }
    .sbm__page { transform: translateY(0); }
  }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.sbm {
  width: min(380px, 90vw);
}

.sbm__slot {
  position: relative;
  height: 96px;
}

.sbm__head {
  position: absolute;
  inset: 0 0 auto 0;
  z-index: 2;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}

.sbm__logo {
  color: #17141a;
  font-weight: 800;
  font-size: clamp(14px, 4vw, 18px);
  line-height: 1;
  font-family: inherit;
  letter-spacing: 0.04em;
}

.sbm__nav {
  display: flex;
  gap: 8px;
  transition: opacity 300ms linear(0, 0.32, 0.538, 0.686, 0.786, 0.855, 0.901, 0.933, 0.954, 0.969, 0.979, 0.986, 0.99, 0.993, 0.995, 0.997, 0.998, 0.999, 0.999, 0.999, 1), transform 300ms linear(0, 0.32, 0.538, 0.686, 0.786, 0.855, 0.901, 0.933, 0.954, 0.969, 0.979, 0.986, 0.99, 0.993, 0.995, 0.997, 0.998, 0.999, 0.999, 0.999, 1);
}
.sbm__nav span {
  width: 20px;
  height: 6px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.2);
}

.sbm__search {
  position: absolute;
  left: 0;
  right: 0;
  top: 56px;
  z-index: 1;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: 0 16px;
  border-top: 1px solid rgba(23, 20, 26, 0.08);
  transform: translateY(0);
  transition: transform 300ms linear(0, 0.32, 0.538, 0.686, 0.786, 0.855, 0.901, 0.933, 0.954, 0.969, 0.979, 0.986, 0.99, 0.993, 0.995, 0.997, 0.998, 0.999, 0.999, 0.999, 1);
}
.sbm__search-box {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(47, 109, 246, 0.1);
}
.sbm__search-icon {
  flex: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid #2f6df6;
}
.sbm__search-text {
  font-weight: 500;
  font-size: clamp(11px, 3vw, 12px);
  line-height: 1;
  font-family: inherit;
  color: rgba(23, 20, 26, 0.72);
}

.sbm.is-scrolled .sbm__nav {
  opacity: 0;
  transform: translateX(8px);
}
.sbm.is-scrolled .sbm__search {
  transform: translateY(-56px);
}
.sbm.is-scrolled .sbm__page {
  transform: translateY(-8px);
}

.sbm.is-demo .sbm__nav {
  animation: sbm-nav-loop 2s linear(0, 0.32, 0.538, 0.686, 0.786, 0.855, 0.901, 0.933, 0.954, 0.969, 0.979, 0.986, 0.99, 0.993, 0.995, 0.997, 0.998, 0.999, 0.999, 0.999, 1) infinite;
}
.sbm.is-demo .sbm__search {
  animation: sbm-search-loop 2s linear(0, 0.32, 0.538, 0.686, 0.786, 0.855, 0.901, 0.933, 0.954, 0.969, 0.979, 0.986, 0.99, 0.993, 0.995, 0.997, 0.998, 0.999, 0.999, 0.999, 1) infinite;
}
.sbm.is-demo .sbm__page {
  animation: sbm-page-loop 2s linear(0, 0.18, 0.328, 0.449, 0.548, 0.629, 0.696, 0.751, 0.796, 0.832, 0.863, 0.887, 0.908, 0.924, 0.938, 0.949, 0.958, 0.966, 0.972, 0.977, 1) infinite;
}

@keyframes sbm-nav-loop {
  0%, 20% {
    opacity: 1;
    transform: translateX(0);
  }
  45%, 70% {
    opacity: 0;
    transform: translateX(8px);
  }
  95%, 100% {
    opacity: 1;
    transform: translateX(0);
  }
}
@keyframes sbm-search-loop {
  0%, 20% {
    transform: translateY(0);
  }
  45%, 70% {
    transform: translateY(-56px);
  }
  95%, 100% {
    transform: translateY(0);
  }
}
@keyframes sbm-page-loop {
  0%, 20% {
    transform: translateY(0);
  }
  45%, 70% {
    transform: translateY(-8px);
  }
  95%, 100% {
    transform: translateY(0);
  }
}
.sbm__page {
  padding: 16px 0 0;
  transform: translateY(0);
  transition: transform 420ms linear(0, 0.18, 0.328, 0.449, 0.548, 0.629, 0.696, 0.751, 0.796, 0.832, 0.863, 0.887, 0.908, 0.924, 0.938, 0.949, 0.958, 0.966, 0.972, 0.977, 1);
}

.sbm__line {
  height: 10px;
  margin: 0 0 12px;
  border-radius: 4px;
  background: rgba(23, 20, 26, 0.08);
}
.sbm__line.short {
  width: 55%;
}

@media (prefers-reduced-motion: reduce) {
  .sbm__nav, .sbm__search, .sbm__page {
    transition: none;
  }
  .sbm.is-demo .sbm__nav, .sbm.is-demo .sbm__search, .sbm.is-demo .sbm__page {
    animation: none !important;
  }
  .sbm.is-demo .sbm__nav {
    opacity: 1;
    transform: translateX(0);
  }
  .sbm.is-demo .sbm__search {
    transform: translateY(0);
  }
  .sbm.is-demo .sbm__page {
    transform: translateY(0);
  }
}

// 실제 페이지: 스크롤하면 아래 검색 줄이 위로 미끄러져 헤더 한 줄 안으로 합쳐진다 (7줄)
var el = document.querySelector('.sbm');
window.addEventListener('scroll', function () {
  el.classList.toggle('is-scrolled', window.scrollY > 20);
}, { passive: true });

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

export type SearchBarMergeProps = {
  logo: string;
  placeholder: string;
  children?: ReactNode;
  /** 검색 줄이 위로 합쳐지는 시간 (기본 300ms) */
  duration?: number;
  /** 관성 lerp 커브(p += (목표-p)*.32 를 20스텝 반복해 구운 linear()) — 기본값이 vanilla 와 같다 */
  easing?: string;
  color?: string;
};

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

const LERP_EASING = "linear(0, .32, .538, .686, .786, .855, .901, .933, .954, .969, .979, .986, .99, .993, .995, .997, .998, .999, .999, .999, 1)";

export default function SearchBarMerge({
  logo,
  placeholder,
  children,
  duration = 300,
  easing = LERP_EASING,
  color = "#2f6df6",
}: SearchBarMergeProps) {
  const ref = useRef<HTMLDivElement>(null);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  useEffect(() => {
    function onScroll() {
      ref.current?.classList.toggle("is-scrolled", window.scrollY > 20);
    }
    window.addEventListener("scroll", onScroll, { passive: true });
    return () => window.removeEventListener("scroll", onScroll);
  }, []);

  return (
    <div ref={ref} className={styles.slot} style={vars}>
      <header className={styles.head}>
        <span className={styles.logo}>{logo}</span>
        <nav className={styles.nav}>{children}</nav>
      </header>
      <div className={styles.search}>
        <span className={styles.searchBox}>
          <span className={styles.searchIcon} />
          <span className={styles.searchText}>{placeholder}</span>
        </span>
      </div>
    </div>
  );
}