02거대 워드마크 내비

<main class="stage">
  <nav class="navbar is-demo">
    <span class="navbar__brand">KINETIC</span>
    <div class="navbar__right">
      <span class="navbar__link">소개</span>
      <span class="navbar__link">가격</span>
      <button class="navbar__cta" type="button">시작하기</button>
    </div>
  </nav>
</main>

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

$duration: $dur-loop;                              // 워드마크가 줄었다 돌아오는 한 주기
$easing: $ease-spring;
$color: $subject-ink;                              // 글자 색

@include stage($stage-yellow);

.navbar {
  width: min(400px, 92vw);
  display: flex;
  align-items: center;
  justify-content: space-between;
  // 320px 폭에서 브랜드+링크+CTA 의 min-content 합이 92vw 를 넘겨 넘쳤다 (body.scrollWidth 실측 — gap·패딩을 뷰포트에 맞춰 줄인다
  gap: clamp($sp-1, 1vw, $sp-4);
  background: $subject-cream;
  border-radius: $r-pill;
  padding: $sp-2 $sp-2 $sp-2 clamp($sp-1, 1.6vw, $sp-4);
  box-shadow: $shadow-raised;
}
// 왼쪽 워드마크만 애니메이션한다 — 스크롤에 맞춰 줄어드는 sticky 헤더를 흉내
.navbar__brand {
  display: inline-flex;
  transform-origin: left center; // 규칙8: 헤더 왼쪽 끝에 붙은 워드마크 — sticky 헤더처럼 좌변을 두고 줄어든다
  color: $color;
  font-weight: 800;
  font-size: clamp(17px, 4.6vw, 23px);
  line-height: 1;
  letter-spacing: .01em;
  animation: brand-shrink $duration $easing infinite;
}
@keyframes brand-shrink {
  0%, 15%   { transform: scale(1); }
  50%       { transform: scale(.78); }
  85%, 100% { transform: scale(1); }
}
// 워드마크 글자 낱개 — index.html 말미 스크립트가 텍스트를 이 span 으로 쪼개고
// 결정론 해시로 --nx0·--ny0·--nr0(출발점) · --wx·--wy·--wr(힘장 경유점) 을 심는다. (형태2차 한 겹, 077 품질기준선)
.char {
  display: inline-block;
  animation: char-flow $duration $easing infinite;
}
.char--space { width: .28em; }

@keyframes char-flow {
  0%, 4%    { transform: translate(var(--nx0, 0), var(--ny0, 14px)) rotate(var(--nr0, 0deg)) scale(.55); opacity: 0; }
  16%       { transform: translate(var(--wx, 0), var(--wy, 4px)) rotate(var(--wr, 0deg)) scale(1.08); opacity: 1; }
  30%, 78%  { transform: translate(0, 0) rotate(0deg) scale(1); opacity: 1; }
  96%, 100% { transform: translate(var(--nx0, 0), var(--ny0, 14px)) rotate(var(--nr0, 0deg)) scale(.55); opacity: 0; }
}

.navbar__right {
  display: flex;
  align-items: center;
  gap: clamp($sp-1, 1.2vw, $sp-4);
}
.navbar__link {
  color: $color;
  opacity: .68;
  font-weight: 600;
  font-size: clamp(11px, 2.6vw, 13px);
  line-height: 1;
}
.navbar__cta {
  border: 0;
  border-radius: $r-pill;
  background: $color;
  color: $subject-cream;
  padding: $sp-2 clamp($sp-1, 1.6vw, $sp-4);
  font-weight: 700;
  font-size: clamp(11px, 2.6vw, 13px);
  line-height: 1;
}

@media (prefers-reduced-motion: reduce) {
  .navbar__brand { animation: none; transform: none; }
  .char { animation: none; transform: none; opacity: 1; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.navbar {
  width: min(400px, 92vw);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(4px, 1vw, 16px);
  background: #fff7e6;
  border-radius: 999px;
  padding: 8px 8px 8px clamp(4px, 1.6vw, 16px);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.navbar__brand {
  display: inline-flex;
  transform-origin: left center;
  color: #17141a;
  font-weight: 800;
  font-size: clamp(17px, 4.6vw, 23px);
  line-height: 1;
  letter-spacing: 0.01em;
  animation: brand-shrink 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes brand-shrink {
  0%, 15% {
    transform: scale(1);
  }
  50% {
    transform: scale(0.78);
  }
  85%, 100% {
    transform: scale(1);
  }
}
.char {
  display: inline-block;
  animation: char-flow 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.char--space {
  width: 0.28em;
}

@keyframes char-flow {
  0%, 4% {
    transform: translate(var(--nx0, 0), var(--ny0, 14px)) rotate(var(--nr0, 0deg)) scale(0.55);
    opacity: 0;
  }
  16% {
    transform: translate(var(--wx, 0), var(--wy, 4px)) rotate(var(--wr, 0deg)) scale(1.08);
    opacity: 1;
  }
  30%, 78% {
    transform: translate(0, 0) rotate(0deg) scale(1);
    opacity: 1;
  }
  96%, 100% {
    transform: translate(var(--nx0, 0), var(--ny0, 14px)) rotate(var(--nr0, 0deg)) scale(0.55);
    opacity: 0;
  }
}
.navbar__right {
  display: flex;
  align-items: center;
  gap: clamp(4px, 1.2vw, 16px);
}

.navbar__link {
  color: #17141a;
  opacity: 0.68;
  font-weight: 600;
  font-size: clamp(11px, 2.6vw, 13px);
  line-height: 1;
}

.navbar__cta {
  border: 0;
  border-radius: 999px;
  background: #17141a;
  color: #fff7e6;
  padding: 8px clamp(4px, 1.6vw, 16px);
  font-weight: 700;
  font-size: clamp(11px, 2.6vw, 13px);
  line-height: 1;
}

@media (prefers-reduced-motion: reduce) {
  .navbar__brand {
    animation: none;
    transform: none;
  }
  .char {
    animation: none;
    transform: none;
    opacity: 1;
  }
}

// 워드마크 글자별 노이즈 오프셋 + 벡터필드 진입 (형태2차) — KINETIC 7글자를 span 으로 쪼개고
// 결정론 해시로 출발점/경유점 변수만 심는다. 프레임은 style.scss 의 char-flow 키프레임이 만든다.
// 기존 brand-shrink(컨테이너 스케일) 와 겹쳐 — 글자는 흩어졌다 힘장을 따라 모이고, 그 위에 워드마크 전체가 줄었다 커진다.
(function () {
  function hash(n) {           // 정수 → 0..1 결정론 난수 (sin 해시)
    var s = Math.sin(n * 127.1 + 311.7) * 43758.5453;
    return s - Math.floor(s);
  }
  document.querySelectorAll('.navbar .navbar__brand').forEach(function (brand) {
    var text = brand.textContent;
    brand.textContent = '';
    for (var c = 0; c < text.length; c++) {
      var ch = document.createElement('span');
      if (text[c] === ' ') { ch.className = 'char char--space'; }
      else {
        ch.className = 'char';
        ch.textContent = text[c];
        var s = c * 13 + 5;
        var h1 = hash(s), h2 = hash(s + 1), h3 = hash(s + 2), h4 = hash(s + 3);
        var ang = h1 * Math.PI * 2;
        var rad = 10 + h2 * 18;
        var x0 = Math.cos(ang) * rad, y0 = 14 + h3 * 12;
        var rot0 = (h4 - .5) * 30;
        var wx = x0 - 0.9 * y0 * 0.55, wy = y0 + 0.9 * x0 * 0.55;
        var wr = rot0 * 0.4;
        ch.style.setProperty('--nx0', x0.toFixed(1) + 'px');
        ch.style.setProperty('--ny0', y0.toFixed(1) + 'px');
        ch.style.setProperty('--nr0', rot0.toFixed(1) + 'deg');
        ch.style.setProperty('--wx', (wx * .6).toFixed(1) + 'px');
        ch.style.setProperty('--wy', (wy * .18 + 3).toFixed(1) + 'px');
        ch.style.setProperty('--wr', wr.toFixed(1) + 'deg');
        ch.style.animationDelay = (-0.05 * c).toFixed(3) + 's';
      }
      brand.appendChild(ch);
    }
  });
})();

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

export type KineticNavProps = {
  brand?: string;
  link1?: string;
  link2?: string;
  cta?: string;
  /** 한 주기(기본 2000ms) */
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type CharVars = CSSProperties & {
  "--nx0"?: string; "--ny0"?: string; "--nr0"?: string;
  "--wx"?: string; "--wy"?: string; "--wr"?: string;
};

/** 정수 → 0..1 결정론 난수 (sin 해시 — vanilla 02 와 동일 계열) */
function hash(n: number): number {
  const s = Math.sin(n * 127.1 + 311.7) * 43758.5453;
  return s - Math.floor(s);
}

/** 한 글자 = 출발점(노이즈) + 힘장 경유점 변수 묶음. vanilla index.html 스크립트와 같은 식. */
function charVars(c: number): CharVars {
  const s = c * 13 + 5;
  const h1 = hash(s), h2 = hash(s + 1), h3 = hash(s + 2), h4 = hash(s + 3);
  const ang = h1 * Math.PI * 2;
  const rad = 10 + h2 * 18;
  const x0 = Math.cos(ang) * rad, y0 = 14 + h3 * 12;
  const rot0 = (h4 - .5) * 30;
  // 회전 힘장 v(p) = ω × p 를 출발점에서 dt 적분 — v = ω*(-y, x), dt=0.55, ω=0.9
  const wx = x0 - 0.9 * y0 * 0.55, wy = y0 + 0.9 * x0 * 0.55;
  const wr = rot0 * 0.4;
  return {
    "--nx0": `${x0.toFixed(1)}px`,
    "--ny0": `${y0.toFixed(1)}px`,
    "--nr0": `${rot0.toFixed(1)}deg`,
    "--wx": `${(wx * .6).toFixed(1)}px`,
    "--wy": `${(wy * .18 + 3).toFixed(1)}px`,
    "--wr": `${wr.toFixed(1)}deg`,
    animationDelay: `${(-0.05 * c).toFixed(3)}s`,
  };
}

export default function KineticNav({
  brand = "KINETIC",
  link1 = "About",
  link2 = "Pricing",
  cta = "Get started",
  duration = 2000,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#17141a",
}: KineticNavProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <div className={styles.stage} style={vars}>
      <nav className={styles.navbar}>
        <span className={styles.brand}>
          {brand.split("").map((ch, c) =>
            ch === " " ? (
              <span key={c} className={styles.charSpace} />
            ) : (
              <span key={c} className={styles.char} style={charVars(c)}>{ch}</span>
            )
          )}
        </span>
        <div className={styles.right}>
          <span className={styles.link}>{link1}</span>
          <span className={styles.link}>{link2}</span>
          <button type="button" className={styles.cta}>{cta}</button>
        </div>
      </nav>
    </div>
  );
}