03Hand-drawn underline

<main class="stage">
  <p class="quote">
    “<span class="hl">Consistency</span> beats skill.”
    <svg class="hl__svg" viewBox="0 0 120 20" preserveAspectRatio="none" aria-hidden="true">
      <path class="hl__path" d="M2 12 C 20 18, 45 6, 62 11 S 100 17, 118 9" />
    </svg>
  </p>
</main>

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

// ── 변수 3개 ─────────────────────────────
$duration: 600ms;              // 손으로 한 획을 긋는 데 걸리는 시간
$easing: $ease-out;
$color: $subject-blue;         // 밑줄 색

// ── 데모 무대 ───────────────────────────────
@include stage($stage-ink);

.quote {
  position: relative;
  display: inline-block;
  margin: 0;
  color: $subject-cream;
  font-weight: 600;
  font-size: clamp(17px, 4.8vw, 23px);
  line-height: 1.7;
  font-family: inherit;
  text-align: center;
}

.hl {
  position: relative;
  color: $subject-cream;
}

// 인용구 바로 아래, 키워드 폭만큼 걸쳐지는 SVG 밑줄 — 살짝 삐뚤한 손글씨 곡선
.hl__svg {
  position: absolute;
  left: 6%;
  right: 46%;                  // "꾸준함" 위치에 맞춘 대략적 폭 (데모 전용 좌표)
  bottom: -6px;
  height: 16px;
  overflow: visible;
}

.hl__path {
  fill: none;
  stroke: $color;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 140;
  stroke-dashoffset: 140;
  animation: draw $duration $easing infinite, draw-thick $duration ease-in-out infinite;
  animation-delay: .2s;
}

@keyframes draw {
  0%   { stroke-dashoffset: 140; }
  35%  { stroke-dashoffset: 0; }
  80%  { stroke-dashoffset: 0; }
  100% { stroke-dashoffset: -140; }
}

// 한 겹: 그어지는 동안 펜 압력처럼 stroke-width 가 요동 — stroke-width 는 transform 이
// 아니라 draw(stroke-dashoffset) 와 병렬로 돌아도 서로 덮지 않는다
@keyframes draw-thick {
  0%   { stroke-width: 3px; }
  25%  { stroke-width: 4.5px; }
  45%  { stroke-width: 3.5px; }
  65%  { stroke-width: 4px; }
  85%  { stroke-width: 3.2px; }
  100% { stroke-width: 3px; }
}

@media (prefers-reduced-motion: reduce) {
  .hl__path { animation: none; stroke-dashoffset: 0; }
}

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);
}

.quote {
  position: relative;
  display: inline-block;
  margin: 0;
  color: #fff7e6;
  font-weight: 600;
  font-size: clamp(17px, 4.8vw, 23px);
  line-height: 1.7;
  font-family: inherit;
  text-align: center;
}

.hl {
  position: relative;
  color: #fff7e6;
}

.hl__svg {
  position: absolute;
  left: 6%;
  right: 46%;
  bottom: -6px;
  height: 16px;
  overflow: visible;
}

.hl__path {
  fill: none;
  stroke: #2f6df6;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 140;
  stroke-dashoffset: 140;
  animation: draw 600ms ease-out infinite, draw-thick 600ms ease-in-out infinite;
  animation-delay: 0.2s;
}

@keyframes draw {
  0% {
    stroke-dashoffset: 140;
  }
  35% {
    stroke-dashoffset: 0;
  }
  80% {
    stroke-dashoffset: 0;
  }
  100% {
    stroke-dashoffset: -140;
  }
}
@keyframes draw-thick {
  0% {
    stroke-width: 3px;
  }
  25% {
    stroke-width: 4.5px;
  }
  45% {
    stroke-width: 3.5px;
  }
  65% {
    stroke-width: 4px;
  }
  85% {
    stroke-width: 3.2px;
  }
  100% {
    stroke-width: 3px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .hl__path {
    animation: none;
    stroke-dashoffset: 0;
  }
}

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

export type HandwrittenUnderlineProps = {
  /** 밑줄이 걸리는 강조어 */
  keyword: ReactNode;
  /** 강조어 뒤 문장 */
  after?: ReactNode;
  /** 한 획을 긋는 데 걸리는 시간 (기본 600ms) */
  duration?: number;
  easing?: string;
  /** 밑줄 색 */
  color?: string;
};

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

export default function HandwrittenUnderline({
  keyword,
  after,
  duration = 600,
  easing = "ease-out",
  color = "#2f6df6",
}: HandwrittenUnderlineProps) {
  const vars: Vars = {
    "--duration": `${duration}ms`,
    "--easing": easing,
    "--color": color,
  };
  return (
    <p className={styles.quote} style={vars}>
      “<span className={styles.hl}>{keyword}</span>{after}
      <svg className={styles.svg} viewBox="0 0 120 20" preserveAspectRatio="none" aria-hidden="true">
        <path className={styles.path} d="M2 12 C 20 18, 45 6, 62 11 S 100 17, 118 9" />
      </svg>
    </p>
  );
}