01층 값이 쌓여 입체가 되는 돌출 글자

<main class="stage">
<div class="ex is-demo" id="ex">
  <p class="ex__badge"><span class="ex__badgeLabel">돌출 깊이</span> <span class="ex__badgeValue" id="exValue">1.0px</span></p>
  <h1 class="ex__word" id="exWord">돌출</h1>
</div>
</main>

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

// 핵심: step 값 하나로 SHADOW_LAYER_COUNT 층의 그림자를 조립한다. step 이 작을 때는
// 얇고 납작한 입체, 클 때는 층이 겹겹이 쌓여 두꺼운 입체로 보인다.

$duration: $dur-loop;
$easing: linear;
$color: $subject-cream;

@include stage($stage-ink);

.ex {
  display: grid;
  gap: $sp-4;
  justify-items: center;
  text-align: center;
}

.ex__badge {
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 247, 230, .1);
  color: $subject-cream;
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
}

.ex__word {
  margin: 0;
  font-weight: 800;
  font-size: clamp(64px, 22vw, 132px);
  line-height: 1;
  white-space: nowrap;
  color: $color;
  will-change: text-shadow;
}

@media (max-width: 340px) {
  .ex__word { font-size: clamp(48px, 24vw, 88px); }
}

@media (prefers-reduced-motion: reduce) {
  .ex__word { transition: none; }
}

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);
}

.ex {
  display: grid;
  gap: 16px;
  justify-items: center;
  text-align: center;
}

.ex__badge {
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.1);
  color: #fff7e6;
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
}

.ex__word {
  margin: 0;
  font-weight: 800;
  font-size: clamp(64px, 22vw, 132px);
  line-height: 1;
  white-space: nowrap;
  color: #fff7e6;
  will-change: text-shadow;
}

@media (max-width: 340px) {
  .ex__word {
    font-size: clamp(48px, 24vw, 88px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .ex__word {
    transition: none;
  }
}

(function () {
  var SHADOW_LAYER_COUNT = 6;
  var STEP_MIN_PX = 1;
  var STEP_MAX_PX = 15;
  var PERIOD_MS = 1000;

  var word = document.getElementById('exWord');
  var value = document.getElementById('exValue');
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  // 계산 레이어: 층 번호(i)가 깊어질수록 명도를 낮춰 아래로 갈수록 어두워지는 입체감을 만든다
  function extrudeColor(i, n) {
    var t = i / n;
    var l = Math.max(6, Math.round(24 - t * 16));
    return 'hsl(232 14% ' + l + '%)';
  }

  // 값(step) 하나로 SHADOW_LAYER_COUNT 개의 그림자를 문자열로 조립한다
  function buildExtrudeShadow(step) {
    var parts = [];
    for (var i = 1; i <= SHADOW_LAYER_COUNT; i++) {
      var d = (i * step).toFixed(2);
      parts.push(d + 'px ' + d + 'px 0 ' + extrudeColor(i, SHADOW_LAYER_COUNT));
    }
    return parts.join(', ');
  }

  function renderExtrude(step) {
    word.style.textShadow = buildExtrudeShadow(step);
    value.textContent = step.toFixed(1) + 'px';
  }

  var startTime = null;
  function loop(now) {
    if (startTime === null) startTime = now;
    var t = (now - startTime) % PERIOD_MS;
    var phase = (Math.sin((t / PERIOD_MS) * Math.PI * 2 - Math.PI / 2) + 1) / 2;
    renderExtrude(STEP_MIN_PX + (STEP_MAX_PX - STEP_MIN_PX) * phase);
    requestAnimationFrame(loop);
  }

  if (reduce) {
    renderExtrude(STEP_MAX_PX);
  } else {
    requestAnimationFrame(loop);
  }
})();

// TextShadowStackExtrude3D — vanilla 판(run/412/demo/01-text-shadow-stack-extrude-3d/index.html) 의 React 포트.
// 값(step) 하나로 SHADOW_LAYER_COUNT 층의 그림자를 조립한다. step 이 작을 때는 얇은 입체,
// 클 때는 층이 겹겹이 쌓여 두꺼운 입체로 보인다.
import { useEffect, useRef, useState } from "react";
import styles from "./TextShadowStackExtrude3D.module.scss";

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

const SHADOW_LAYER_COUNT = 6;
const STEP_MIN_PX = 1;
const STEP_MAX_PX = 15;
const PERIOD_MS = 1000;

function extrudeColor(i: number, n: number): string {
  const t = i / n;
  const l = Math.max(6, Math.round(24 - t * 16));
  return "hsl(232 14% " + l + "%)";
}

function buildExtrudeShadow(step: number): string {
  const parts: string[] = [];
  for (let i = 1; i <= SHADOW_LAYER_COUNT; i++) {
    const d = (i * step).toFixed(2);
    parts.push(d + "px " + d + "px 0 " + extrudeColor(i, SHADOW_LAYER_COUNT));
  }
  return parts.join(", ");
}

export default function TextShadowStackExtrude3D() {
  const wordRef = useRef<HTMLHeadingElement | null>(null);
  const valueRef = useRef<HTMLSpanElement | null>(null);
  const t0Ref = useRef<number>(0) as Box<number>;
  const frameRef = useRef<number>(0) as Box<number>;
  const [demo] = useState(true);
  const [reduce, setReduce] = useState(false);

  function render(step: number): void {
    const word = wordRef.current;
    const value = valueRef.current;
    if (!word || !value) return;
    word.style.textShadow = buildExtrudeShadow(step);
    value.textContent = step.toFixed(1) + "px";
  }

  useEffect(() => {
    setReduce(window.matchMedia("(prefers-reduced-motion: reduce)").matches);
  }, []);

  useEffect(() => {
    if (reduce) {
      render(STEP_MAX_PX);
      return;
    }
    function loop(now: number): void {
      if (t0Ref.current === 0) t0Ref.current = now;
      const t = (now - t0Ref.current) % PERIOD_MS;
      const phase = (Math.sin((t / PERIOD_MS) * Math.PI * 2 - Math.PI / 2) + 1) / 2;
      render(STEP_MIN_PX + (STEP_MAX_PX - STEP_MIN_PX) * phase);
      frameRef.current = requestAnimationFrame(loop);
    }
    frameRef.current = requestAnimationFrame(loop);
    return () => cancelAnimationFrame(frameRef.current);
  }, [reduce]);

  const cls = [styles.ex, demo ? styles.isDemo : ""].filter(Boolean).join(" ");
  return (
    <main className={styles.stage}>
      <div className={cls}>
        <p className={styles.badge}><span>돌출 깊이</span> <span ref={valueRef}>1.0px</span></p>
        <h1 className={styles.word} ref={wordRef}>돌출</h1>
      </div>
    </main>
  );
}