07Notch safe-area padding — margin that pushes content clear of a screen's cut-out edges

<main class="stage">
<div class="wrap is-demo" id="wrap">
  <div class="frameOuter">
    <div class="notchTop" id="notchTop"></div>
    <div class="frameInner">
      <div class="content" id="content">
        <span class="pill" id="pill">Content</span>
      </div>
    </div>
    <div class="notchBottom" id="notchBottom"></div>
  </div>
  <input class="slider" id="slider" type="range" min="0" max="100" value="0" aria-label="Safe area simulation">
  <div class="readout" id="readout">Top —px · bottom —px</div>
</div>
</main>

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

// 계산 겹은 index.html 의 apply() 에 있다 — 슬라이더 진행률(t)로 --safe-top/--safe-bottom
// 커스텀 프로퍼티를 실측 px 로 채우고 getComputedStyle 로 실제 렌더된 padding 을 다시 잰다.
// 실사용 코드는 env(safe-area-inset-*) 를 그대로 쓰고, 데스크톱은 그 값이 항상 0px 이라
// 시뮬레이션용 --safe-top/--safe-bottom 을 max() 로 겹쳐 잰다(데모 전용 값이지 대체가 아니다).
@include stage($stage-orange);

.wrap {
  width: 300px;
  display: flex;
  flex-direction: column;
  gap: $sp-3;
  align-items: center;
}

.frameOuter {
  width: 200px;
  border-radius: $r-card;
  border: 3px solid $subject-ink;
  overflow: hidden;
  background: $subject-ink;
}

.notchTop,
.notchBottom {
  height: 10px;
  background: rgba($subject-ink, .9);
  display: flex;
  justify-content: center;

  &::after {
    content: "";
    width: 40px;
    height: 6px;
    border-radius: $r-pill;
    background: $subject-cream;
    opacity: .3;
    align-self: center;
  }
}

.frameInner {
  background: $subject-cream;
  min-height: 120px;
  display: flex;
  align-items: stretch;
}

.content {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  // 실사용 규칙 — 실제 기기 안전 영역과 시뮬레이션 값 중 큰 쪽을 쓴다
  padding-top: max(var(--safe-top, 0px), env(safe-area-inset-top));
  padding-bottom: max(var(--safe-bottom, 0px), env(safe-area-inset-bottom));
  padding-left: $sp-3;
  padding-right: $sp-3;
  transition: padding $dur-base $ease-out;
}

.pill {
  border-radius: $r-pill;
  background: $subject-orange-deep;
  color: $subject-cream;
  padding: $sp-1 $sp-3;
  font-size: 11px;
  font-weight: 700;
}

.slider {
  width: 220px;
  accent-color: $subject-orange-deep;
}

.readout {
  color: $subject-ink;
  font-size: 11px;
}

@media (max-width: 340px) {
  .wrap { width: 260px; gap: $sp-2; }
  .frameOuter, .slider { width: 170px; }
  .frameInner { min-height: 84px; }
  .notchTop, .notchBottom { height: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  // reduce: 자동 루프의 오가는 진행만 멈춘다(슬라이더 실사용 조작은 즉시 반영)
  .content { transition: 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);
}

.wrap {
  width: 300px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
}

.frameOuter {
  width: 200px;
  border-radius: 16px;
  border: 3px solid #17141a;
  overflow: hidden;
  background: #17141a;
}

.notchTop,
.notchBottom {
  height: 10px;
  background: rgba(23, 20, 26, 0.9);
  display: flex;
  justify-content: center;
}
.notchTop::after,
.notchBottom::after {
  content: "";
  width: 40px;
  height: 6px;
  border-radius: 999px;
  background: #fff7e6;
  opacity: 0.3;
  align-self: center;
}

.frameInner {
  background: #fff7e6;
  min-height: 120px;
  display: flex;
  align-items: stretch;
}

.content {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: max(var(--safe-top, 0px), env(safe-area-inset-top));
  padding-bottom: max(var(--safe-bottom, 0px), env(safe-area-inset-bottom));
  padding-left: 12px;
  padding-right: 12px;
  transition: padding 300ms ease-out;
}

.pill {
  border-radius: 999px;
  background: #c93000;
  color: #fff7e6;
  padding: 4px 12px;
  font-size: 11px;
  font-weight: 700;
}

.slider {
  width: 220px;
  accent-color: #c93000;
}

.readout {
  color: #17141a;
  font-size: 11px;
}

@media (max-width: 340px) {
  .wrap {
    width: 260px;
    gap: 8px;
  }
  .frameOuter, .slider {
    width: 170px;
  }
  .frameInner {
    min-height: 84px;
  }
  .notchTop, .notchBottom {
    height: 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .content {
    transition: none;
  }
}

(function () {
  var SAFE_AREA_SCALE = 1.0;
  var STEP_MS_TOTAL = 2000;
  var MAX_INSET_PX = 24;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var wrap = document.getElementById('wrap');
  var root = document.documentElement;
  var slider = document.getElementById('slider');
  var content = document.getElementById('content');
  var readout = document.getElementById('readout');
  var isDemo = true;

  function apply(t) {
    // t: 0~1, 시뮬레이션한 기기 안전 영역 진행률 — env() 변수를 실측 CSS 커스텀 프로퍼티로 대입한다
    var top = Math.round(MAX_INSET_PX * t * SAFE_AREA_SCALE);
    var bottom = Math.round(MAX_INSET_PX * t);
    root.style.setProperty('--safe-top', top + 'px');
    root.style.setProperty('--safe-bottom', bottom + 'px');
    slider.value = String(Math.round(t * 100));
    // 실측 — padding-top 이 실제로 몇 px 렌더됐는지 getComputedStyle 로 다시 잰다
    var cs = getComputedStyle(content);
    readout.textContent = 'Top ' + parseFloat(cs.paddingTop).toFixed(0) + 'px · bottom ' + parseFloat(cs.paddingBottom).toFixed(0) + 'px';
  }

  function human() { if (isDemo) { wrap.classList.remove('is-demo'); isDemo = false; } }
  slider.addEventListener('input', function () {
    human();
    apply(Number(slider.value) / 100);
  });
  slider.addEventListener('pointerdown', human);

  var start = 0;
  function loop(ts) {
    if (!start) start = ts;
    if (isDemo && !reduce) {
      var phase = ((ts - start) % STEP_MS_TOTAL) / STEP_MS_TOTAL;
      var t = phase < 0.5 ? phase * 2 : (1 - phase) * 2;
      apply(t);
    }
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

// SafeArea — vanilla 판(run/376/demo/07-safe-area/index.html) 의 React 포트.
// 슬라이더 진행률(t)로 --safe-top/--safe-bottom 커스텀 프로퍼티를 실측 px 로 채우고
// getComputedStyle 로 실제 렌더된 padding 을 다시 잰다. 실사용 padding 규칙은 CSS 의
// env(safe-area-inset-*) 를 그대로 쓰고 --safe-top/--safe-bottom 은 데모 시뮬레이션 값이다.
import { useEffect, useRef } from "react";
import styles from "./SafeArea.module.scss";

type Box<T> = { current: T };

const SAFE_AREA_SCALE = 1.0;
const STEP_MS_TOTAL = 2000;
const MAX_INSET_PX = 24;

export default function SafeArea() {
  const wrapRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const sliderRef = useRef(null) as unknown as Box<HTMLInputElement>;
  const contentRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const readoutRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const rafRef = useRef(0) as unknown as Box<number>;

  useEffect(() => {
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    const wrap = wrapRef.current;
    const slider = sliderRef.current;
    const content = contentRef.current;
    const readout = readoutRef.current;
    if (!wrap || !slider || !content || !readout) return;

    const root = document.documentElement;
    let isDemo = true;

    function apply(t: number) {
      const top = Math.round(MAX_INSET_PX * t * SAFE_AREA_SCALE);
      const bottom = Math.round(MAX_INSET_PX * t);
      root.style.setProperty("--safe-top", top + "px");
      root.style.setProperty("--safe-bottom", bottom + "px");
      slider!.value = String(Math.round(t * 100));
      const cs = getComputedStyle(content!);
      readout!.textContent =
        "위 " + parseFloat(cs.paddingTop).toFixed(0) + "px · 아래 " + parseFloat(cs.paddingBottom).toFixed(0) + "px";
    }

    function human() {
      if (isDemo) { wrap!.classList.remove(styles.isDemo); isDemo = false; }
    }
    function onInput() { human(); apply(Number(slider!.value) / 100); }
    slider.addEventListener("input", onInput);
    slider.addEventListener("pointerdown", human);

    let start = 0;
    function loop(ts: number) {
      if (!start) start = ts;
      if (isDemo && !reduce) {
        const phase = ((ts - start) % STEP_MS_TOTAL) / STEP_MS_TOTAL;
        const t = phase < 0.5 ? phase * 2 : (1 - phase) * 2;
        apply(t);
      }
      rafRef.current = requestAnimationFrame(loop);
    }
    rafRef.current = requestAnimationFrame(loop);

    return () => {
      slider!.removeEventListener("input", onInput);
      slider!.removeEventListener("pointerdown", human);
      cancelAnimationFrame(rafRef.current);
      root.style.setProperty("--safe-top", "0px");
      root.style.setProperty("--safe-bottom", "0px");
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.wrap + " " + styles.isDemo} ref={wrapRef}>
        <div className={styles.frameOuter}>
          <div className={styles.notchTop}></div>
          <div className={styles.frameInner}>
            <div className={styles.content} ref={contentRef}>
              <span className={styles.pill}>본문</span>
            </div>
          </div>
          <div className={styles.notchBottom}></div>
        </div>
        <input
          className={styles.slider}
          ref={sliderRef}
          type="range"
          min={0}
          max={100}
          defaultValue={0}
          aria-label="안전 영역 시뮬레이션"
        />
        <div className={styles.readout} ref={readoutRef}>위 —px · 아래 —px</div>
      </div>
    </main>
  );
}