02Marker overlap

<main class="stage">
  <p class="line">The heart of this plan is <span class="hl">unlimited storage</span>.</p>
</main>

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

// ── 변수 3개 ─────────────────────────────
$duration: $dur-loop;
$easing: $ease-spring;
$color: $subject-blue;         // 두 번째 스트로크 색 (첫 번째는 무대 노랑)

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

.line {
  max-width: 92%;
  margin: 0;
  color: $stage-ink;
  font-weight: 700;
  font-size: clamp(16px, 4.6vw, 22px);
  line-height: 1.6;
  font-family: inherit;
  text-align: center;
}

// 같은 자리에 두 겹의 마커 스트로크를 서로 다른 각도로 겹쳐 칠한다 (018 체크 게이트와 무관 — 여긴 체크 아이콘이 아니다)
.hl {
  position: relative;
  isolation: isolate;          // z-index:-1 을 이 안에 가둬 무대 배경 뒤로 숨지 않게 한다
  padding: 0 $sp-1;

  &::before, &::after {
    content: "";
    position: absolute;
    inset: 10% -2% 4%;
    border-radius: $r-xs;
    transform: scaleX(0);
    transform-origin: left center; // 규칙8: 마커 겹칠 왼쪽 칠함
    mix-blend-mode: multiply;
    z-index: -1;
  }
  &::before {
    background: $stage-yellow;
    rotate: -1.2deg;
    animation: mark $duration $easing infinite, mark-thick-1 $duration ease-in-out infinite;
  }
  &::after {
    background: $color;
    opacity: .55;
    rotate: 1deg;
    animation: mark $duration $easing infinite .3s, mark-thick-2 $duration ease-in-out infinite .15s;
  }
}

@keyframes mark {
  0%   { transform: scaleX(0); }
  20%  { transform: scaleX(1); }
  75%  { transform: scaleX(1); }
  100% { transform: scaleX(0); }
}

// 한 겹: 각 스트로크의 위·아래 두께 요동 — inset(top/bottom) 변조라 transform 아님.
// 두 스트로크가 서로 다른 위상으로 출렁여 겹침 가장자리가 살아 움직인다
@keyframes mark-thick-1 {
  0%   { inset: 10% -2% 4%; }
  25%  { inset: 8% -2% 5.5%; }
  50%  { inset: 11.5% -2% 3%; }
  75%  { inset: 9% -2% 6%; }
  100% { inset: 10% -2% 4%; }
}

@keyframes mark-thick-2 {
  0%   { inset: 10% -2% 4%; }
  30%  { inset: 12% -2% 2.5%; }
  55%  { inset: 7.5% -2% 6.5%; }
  80%  { inset: 11% -2% 3.5%; }
  100% { inset: 10% -2% 4%; }
}

@media (prefers-reduced-motion: reduce) {
  .hl::before, .hl::after { animation: none; transform: scaleX(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);
}

.line {
  max-width: 92%;
  margin: 0;
  color: #17141a;
  font-weight: 700;
  font-size: clamp(16px, 4.6vw, 22px);
  line-height: 1.6;
  font-family: inherit;
  text-align: center;
}

.hl {
  position: relative;
  isolation: isolate;
  padding: 0 4px;
}
.hl::before, .hl::after {
  content: "";
  position: absolute;
  inset: 10% -2% 4%;
  border-radius: 4px;
  transform: scaleX(0);
  transform-origin: left center;
  mix-blend-mode: multiply;
  z-index: -1;
}
.hl::before {
  background: #ffd23f;
  rotate: -1.2deg;
  animation: mark 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite, mark-thick-1 2s ease-in-out infinite;
}
.hl::after {
  background: #2f6df6;
  opacity: 0.55;
  rotate: 1deg;
  animation: mark 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite 0.3s, mark-thick-2 2s ease-in-out infinite 0.15s;
}

@keyframes mark {
  0% {
    transform: scaleX(0);
  }
  20% {
    transform: scaleX(1);
  }
  75% {
    transform: scaleX(1);
  }
  100% {
    transform: scaleX(0);
  }
}
@keyframes mark-thick-1 {
  0% {
    inset: 10% -2% 4%;
  }
  25% {
    inset: 8% -2% 5.5%;
  }
  50% {
    inset: 11.5% -2% 3%;
  }
  75% {
    inset: 9% -2% 6%;
  }
  100% {
    inset: 10% -2% 4%;
  }
}
@keyframes mark-thick-2 {
  0% {
    inset: 10% -2% 4%;
  }
  30% {
    inset: 12% -2% 2.5%;
  }
  55% {
    inset: 7.5% -2% 6.5%;
  }
  80% {
    inset: 11% -2% 3.5%;
  }
  100% {
    inset: 10% -2% 4%;
  }
}
@media (prefers-reduced-motion: reduce) {
  .hl::before, .hl::after {
    animation: none;
    transform: scaleX(1);
  }
}

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

export type MarkerOverlapProps = {
  before: ReactNode;
  keyword: ReactNode;
  after?: ReactNode;
  duration?: number;
  easing?: string;
  /** 두 번째(위) 스트로크 색 */
  color?: string;
};

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

export default function MarkerOverlap({
  before,
  keyword,
  after,
  duration = 2000,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#2f6df6",
}: MarkerOverlapProps) {
  const vars: Vars = {
    "--duration": `${duration}ms`,
    "--easing": easing,
    "--color": color,
  };
  return (
    <p className={styles.line}>
      {before} <span className={styles.hl} style={vars}>{keyword}</span>{after}
    </p>
  );
}