01Neon text flicker

<main class="stage is-demo">
  <h1 class="neon">GODRICH</h1>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;   // 2s — 깜빡임 한 주기
$easing: linear;
$color: #ff2e63;        // 네온 핑크

@include stage($stage-ink);

.neon {
  margin: 0;
  font: 800 clamp(30px, 11vmin, 56px)/1 "Segoe UI", -apple-system, "Noto Sans KR", sans-serif;
  letter-spacing: .04em;
  color: $stage-paper;
  text-shadow:
    0 0 $sp-1 $color,
    0 0 $sp-2 $color,
    0 0 $sp-4 rgba($color, .8),
    0 0 $sp-8 rgba($color, .6),
    0 0 $sp-12 rgba($color, .35);
}

// opacity 하나만 흔들어도 색+text-shadow 전체가 같이 어두워진다 — transform·opacity 원칙 유지
.stage.is-demo .neon {
  animation: flicker $duration $easing infinite;
}

@keyframes flicker {
  0%   { opacity: 1; }
  6%   { opacity: .3; }
  14%  { opacity: 1; }
  20%  { opacity: 1; }
  26%  { opacity: .4; }
  34%  { opacity: 1; }
  50%  { opacity: 1; }
  56%  { opacity: .25; }
  64%  { opacity: 1; }
  80%  { opacity: 1; }
  86%  { opacity: .35; }
  94%  { opacity: 1; }
  100% { opacity: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .neon { animation: 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: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.neon {
  margin: 0;
  font: 800 clamp(30px, 11vmin, 56px)/1 "Segoe UI", -apple-system, "Noto Sans KR", sans-serif;
  letter-spacing: 0.04em;
  color: #ffffff;
  text-shadow: 0 0 4px #ff2e63, 0 0 8px #ff2e63, 0 0 16px rgba(255, 46, 99, 0.8), 0 0 32px rgba(255, 46, 99, 0.6), 0 0 48px rgba(255, 46, 99, 0.35);
}

.stage.is-demo .neon {
  animation: flicker 2s linear infinite;
}

@keyframes flicker {
  0% {
    opacity: 1;
  }
  6% {
    opacity: 0.3;
  }
  14% {
    opacity: 1;
  }
  20% {
    opacity: 1;
  }
  26% {
    opacity: 0.4;
  }
  34% {
    opacity: 1;
  }
  50% {
    opacity: 1;
  }
  56% {
    opacity: 0.25;
  }
  64% {
    opacity: 1;
  }
  80% {
    opacity: 1;
  }
  86% {
    opacity: 0.35;
  }
  94% {
    opacity: 1;
  }
  100% {
    opacity: 1;
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .neon {
    animation: none;
    opacity: 1;
  }
}

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

export type NeonTextFlickerProps = {
  /** 화면에 뜨는 글자 (기본 "GODRICH") */
  text?: string;
  /** 깜빡임 한 주기 (기본 2000ms) */
  duration?: number;
  color?: string;
};

export default function NeonTextFlicker({
  text = "GODRICH",
  duration = 2000,
  color = "#ff2e63",
}: NeonTextFlickerProps) {
  const vars: CSSProperties = { "--duration": `${duration}ms`, "--color": color } as CSSProperties;
  return (
    <div className={styles.stage} style={vars}>
      <h1 className={styles.neon}>{text}</h1>
    </div>
  );
}