06Chữ chạy vòng quanh

<main class="stage">
  <button type="button" class="totop" aria-label="Lên đầu trang">
    <svg class="totop__ring is-demo" viewBox="0 0 64 64" aria-hidden="true">
      <defs>
        <path id="ring-path" d="M32,32 m-24,0 a24,24 0 1,1 48,0 a24,24 0 1,1 -48,0"/>
      </defs>
      <text class="totop__ring-text">
        <textPath href="#ring-path" startOffset="0%">SCROLL TO TOP · SCROLL TO TOP · </textPath>
      </text>
    </svg>
    <svg class="totop__arrow" viewBox="0 0 24 24" aria-hidden="true"><polyline points="5,15 12,8 19,15"/></svg>
  </button>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: 8s;
$easing: linear;
$color: $subject-ink;      // 글자 색

@include stage($stage-yellow);

.totop {
  position: relative;
  width: 72px; height: 72px;
  border: 0;
  border-radius: $r-pill;
  background: transparent;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.totop__ring {
  position: absolute;
  inset: 0;
  width: 72px; height: 72px;
  transform-origin: center;
}
// 상시 반복 — 실제 사용도 버튼이 떠 있는 동안 계속 돈다
.totop__ring.is-demo { animation: ring-spin $duration $easing infinite; }
@keyframes ring-spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

.totop__ring-text {
  font: 700 6.4px/1 -apple-system, "Segoe UI", sans-serif;
  letter-spacing: .12em;
  fill: $color;
}

.totop__arrow {
  position: relative;
  display: block;
  width: 22px; height: 22px;
  fill: none;
  stroke: $subject-ink;
  stroke-width: 2.4;
  stroke-linecap: round;
  stroke-linejoin: round;
  background: $stage-paper;
  border-radius: $r-pill;
  padding: $sp-2;
  box-shadow: $shadow-raised;
  box-sizing: content-box;
}

@media (prefers-reduced-motion: reduce) {
  .totop__ring.is-demo { animation: none; }
}

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);
}

.totop {
  position: relative;
  width: 72px;
  height: 72px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.totop__ring {
  position: absolute;
  inset: 0;
  width: 72px;
  height: 72px;
  transform-origin: center;
}

.totop__ring.is-demo {
  animation: ring-spin 8s linear infinite;
}

@keyframes ring-spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}
.totop__ring-text {
  font: 700 6.4px/1 -apple-system, "Segoe UI", sans-serif;
  letter-spacing: 0.12em;
  fill: #17141a;
}

.totop__arrow {
  position: relative;
  display: block;
  width: 22px;
  height: 22px;
  fill: none;
  stroke: #17141a;
  stroke-width: 2.4;
  stroke-linecap: round;
  stroke-linejoin: round;
  background: #ffffff;
  border-radius: 999px;
  padding: 8px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  box-sizing: content-box;
}

@media (prefers-reduced-motion: reduce) {
  .totop__ring.is-demo {
    animation: none;
  }
}

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

export type TextRotateButtonProps = {
  /** 한 바퀴 도는 시간 (기본 8s) */
  duration?: number;
  label?: string;
  /** SVG textPath id — 한 페이지에 여러 개 두면 서로 다른 값을 준다 (기본 "totop-ring-path") */
  pathId?: string;
};

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

export default function TextRotateButton({
  duration = 8000,
  label = "SCROLL TO TOP",
  pathId = "totop-ring-path",
}: TextRotateButtonProps) {
  const vars: Vars = { "--duration": `${duration}ms` };
  const text = `${label} · ${label} · `;
  return (
    <button
      type="button"
      className={styles.totop}
      style={vars}
      aria-label="맨 위로"
      onClick={() => window.scrollTo({ top: 0, behavior: "smooth" })}
    >
      <svg className={styles.ring} viewBox="0 0 64 64" aria-hidden="true">
        <defs>
          <path id={pathId} d="M32,32 m-24,0 a24,24 0 1,1 48,0 a24,24 0 1,1 -48,0" />
        </defs>
        <text className={styles.ringText}>
          <textPath href={`#${pathId}`} startOffset="0%">{text}</textPath>
        </text>
      </svg>
      <svg className={styles.arrow} viewBox="0 0 24 24" aria-hidden="true">
        <polyline points="5,15 12,8 19,15" />
      </svg>
    </button>
  );
}