04Nút tròn + mũi tên hover

<main class="stage">
  <a class="cx-btn is-demo" href="#" aria-label="Next">
    <span class="cx-btn__arrow cx-btn__arrow--a"></span>
    <span class="cx-btn__arrow cx-btn__arrow--b"></span>
    <span class="cx-btn__trail cx-btn__trail--a" aria-hidden="true"></span>
    <span class="cx-btn__trail cx-btn__trail--b" aria-hidden="true"></span>
  </a>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;   // is-demo 강제 루프 주기. 실제 호버 전환은 아래 280ms 를 쓴다
$easing: $ease-elastic;  // 고무줄식 오버슛 — 커졌다 살짝 되돌아와 멈춘다
$color: $subject-blue;

@include stage($stage-paper);

.cx-btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: 2px solid $subject-ink;
  text-decoration: none;
  transform: scale(1);
  transition: transform 280ms $easing, border-color 280ms $easing;
}
.cx-btn:hover { transform: scale(1.06); border-color: $color; }

.cx-btn__arrow {
  position: absolute;
  width: 16px;
  height: 16px;
  border-top: 2px solid $color;
  border-right: 2px solid $color;
  transform: rotate(45deg);
}

// 두 화살표가 겹쳐 있다가 호버 시 한쪽은 오른쪽으로 빠지고 다른 한쪽이 왼쪽에서 들어와 자리를 대신한다
.cx-btn__arrow--a { opacity: 1; transform: rotate(45deg) translateX(0); transition: transform 280ms $easing, opacity 280ms $easing; }
.cx-btn__arrow--b { opacity: 0; transform: rotate(45deg) translateX(-16px); transition: transform 280ms $easing, opacity 280ms $easing; }
.cx-btn:hover .cx-btn__arrow--a { opacity: 0; transform: rotate(45deg) translateX(16px); }
.cx-btn:hover .cx-btn__arrow--b { opacity: 1; transform: rotate(45deg) translateX(0); }

// 트레일 파티클 — 교차하는 두 화살표 각각 뒤로 작은 점이 지연·감쇠하며 따라붙는다
.cx-btn__trail {
  position: absolute;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: $color;
  opacity: 0;
}
@keyframes cx-trail-a-hover {
  0%   { opacity: 0; transform: translateX(0) rotate(45deg); }
  50%  { opacity: .4; transform: translateX(10px) rotate(45deg); }
  100% { opacity: 0; transform: translateX(16px) rotate(45deg); }
}
@keyframes cx-trail-b-hover {
  0%   { opacity: 0; transform: translateX(-16px) rotate(45deg); }
  50%  { opacity: .4; transform: translateX(-4px) rotate(45deg); }
  100% { opacity: 0; transform: translateX(0) rotate(45deg); }
}
.cx-btn:hover .cx-btn__trail--a { animation: cx-trail-a-hover 280ms $ease-out forwards; }
.cx-btn:hover .cx-btn__trail--b { animation: cx-trail-b-hover 280ms $ease-out forwards; }

// 데모 루프: is-demo 는 :hover 를 흉내 낸 keyframes 로 무한 반복 (헤드리스는 :hover 를 못 건다)
@keyframes cx-btn-scale {
  0%, 20% { transform: scale(1); border-color: $subject-ink; }
  50%, 70% { transform: scale(1.06); border-color: $color; }
  100% { transform: scale(1); border-color: $subject-ink; }
}
@keyframes cx-arrow-a {
  0%, 20% { opacity: 1; transform: rotate(45deg) translateX(0); }
  50%, 70% { opacity: 0; transform: rotate(45deg) translateX(16px); }
  100% { opacity: 1; transform: rotate(45deg) translateX(0); }
}
@keyframes cx-arrow-b {
  0%, 20% { opacity: 0; transform: rotate(45deg) translateX(-16px); }
  50%, 70% { opacity: 1; transform: rotate(45deg) translateX(0); }
  100% { opacity: 0; transform: rotate(45deg) translateX(-16px); }
}
@keyframes cx-trail-a-loop {
  0%, 20%   { opacity: 0; transform: translateX(0) rotate(45deg); }
  40%       { opacity: .4; transform: translateX(10px) rotate(45deg); }
  50%, 70%  { opacity: 0; transform: translateX(16px) rotate(45deg); }
  100%      { opacity: 0; transform: translateX(0) rotate(45deg); }
}
@keyframes cx-trail-b-loop {
  0%, 20%   { opacity: 0; transform: translateX(-16px) rotate(45deg); }
  55%       { opacity: .4; transform: translateX(-4px) rotate(45deg); }
  70%, 100% { opacity: 0; transform: translateX(0) rotate(45deg); }
}
.cx-btn.is-demo { animation: cx-btn-scale $duration $easing infinite; }
.cx-btn.is-demo .cx-btn__arrow--a { animation: cx-arrow-a $duration $easing infinite; }
.cx-btn.is-demo .cx-btn__arrow--b { animation: cx-arrow-b $duration $easing infinite; }
.cx-btn.is-demo .cx-btn__trail--a { animation: cx-trail-a-loop $duration $ease-out infinite; }
.cx-btn.is-demo .cx-btn__trail--b { animation: cx-trail-b-loop $duration $ease-out infinite; }

@media (prefers-reduced-motion: reduce) {
  .cx-btn,
  .cx-btn.is-demo,
  .cx-btn__arrow--a,
  .cx-btn__arrow--b,
  .cx-btn.is-demo .cx-btn__arrow--a,
  .cx-btn.is-demo .cx-btn__arrow--b {
    animation: none !important;
    transition: none !important;
  }
  .cx-btn { transform: scale(1) !important; border-color: $subject-ink !important; }
  .cx-btn__arrow--a { opacity: 1 !important; transform: rotate(45deg) translateX(0) !important; }
  .cx-btn__arrow--b { opacity: 0 !important; transform: rotate(45deg) translateX(-16px) !important; }
  .cx-btn__trail,
  .cx-btn:hover .cx-btn__trail,
  .cx-btn.is-demo .cx-btn__trail {
    animation: none !important;
    opacity: 0 !important;
  }
}

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

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

.cx-btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: 2px solid #17141a;
  text-decoration: none;
  transform: scale(1);
  transition: transform 280ms cubic-bezier(0.34, 1.56, 0.64, 1), border-color 280ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.cx-btn:hover {
  transform: scale(1.06);
  border-color: #2f6df6;
}

.cx-btn__arrow {
  position: absolute;
  width: 16px;
  height: 16px;
  border-top: 2px solid #2f6df6;
  border-right: 2px solid #2f6df6;
  transform: rotate(45deg);
}

.cx-btn__arrow--a {
  opacity: 1;
  transform: rotate(45deg) translateX(0);
  transition: transform 280ms cubic-bezier(0.34, 1.56, 0.64, 1), opacity 280ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.cx-btn__arrow--b {
  opacity: 0;
  transform: rotate(45deg) translateX(-16px);
  transition: transform 280ms cubic-bezier(0.34, 1.56, 0.64, 1), opacity 280ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.cx-btn:hover .cx-btn__arrow--a {
  opacity: 0;
  transform: rotate(45deg) translateX(16px);
}

.cx-btn:hover .cx-btn__arrow--b {
  opacity: 1;
  transform: rotate(45deg) translateX(0);
}

.cx-btn__trail {
  position: absolute;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: #2f6df6;
  opacity: 0;
}

@keyframes cx-trail-a-hover {
  0% {
    opacity: 0;
    transform: translateX(0) rotate(45deg);
  }
  50% {
    opacity: 0.4;
    transform: translateX(10px) rotate(45deg);
  }
  100% {
    opacity: 0;
    transform: translateX(16px) rotate(45deg);
  }
}
@keyframes cx-trail-b-hover {
  0% {
    opacity: 0;
    transform: translateX(-16px) rotate(45deg);
  }
  50% {
    opacity: 0.4;
    transform: translateX(-4px) rotate(45deg);
  }
  100% {
    opacity: 0;
    transform: translateX(0) rotate(45deg);
  }
}
.cx-btn:hover .cx-btn__trail--a {
  animation: cx-trail-a-hover 280ms ease-out forwards;
}

.cx-btn:hover .cx-btn__trail--b {
  animation: cx-trail-b-hover 280ms ease-out forwards;
}

@keyframes cx-btn-scale {
  0%, 20% {
    transform: scale(1);
    border-color: #17141a;
  }
  50%, 70% {
    transform: scale(1.06);
    border-color: #2f6df6;
  }
  100% {
    transform: scale(1);
    border-color: #17141a;
  }
}
@keyframes cx-arrow-a {
  0%, 20% {
    opacity: 1;
    transform: rotate(45deg) translateX(0);
  }
  50%, 70% {
    opacity: 0;
    transform: rotate(45deg) translateX(16px);
  }
  100% {
    opacity: 1;
    transform: rotate(45deg) translateX(0);
  }
}
@keyframes cx-arrow-b {
  0%, 20% {
    opacity: 0;
    transform: rotate(45deg) translateX(-16px);
  }
  50%, 70% {
    opacity: 1;
    transform: rotate(45deg) translateX(0);
  }
  100% {
    opacity: 0;
    transform: rotate(45deg) translateX(-16px);
  }
}
@keyframes cx-trail-a-loop {
  0%, 20% {
    opacity: 0;
    transform: translateX(0) rotate(45deg);
  }
  40% {
    opacity: 0.4;
    transform: translateX(10px) rotate(45deg);
  }
  50%, 70% {
    opacity: 0;
    transform: translateX(16px) rotate(45deg);
  }
  100% {
    opacity: 0;
    transform: translateX(0) rotate(45deg);
  }
}
@keyframes cx-trail-b-loop {
  0%, 20% {
    opacity: 0;
    transform: translateX(-16px) rotate(45deg);
  }
  55% {
    opacity: 0.4;
    transform: translateX(-4px) rotate(45deg);
  }
  70%, 100% {
    opacity: 0;
    transform: translateX(0) rotate(45deg);
  }
}
.cx-btn.is-demo {
  animation: cx-btn-scale 2s cubic-bezier(0.34, 1.56, 0.64, 1) infinite;
}

.cx-btn.is-demo .cx-btn__arrow--a {
  animation: cx-arrow-a 2s cubic-bezier(0.34, 1.56, 0.64, 1) infinite;
}

.cx-btn.is-demo .cx-btn__arrow--b {
  animation: cx-arrow-b 2s cubic-bezier(0.34, 1.56, 0.64, 1) infinite;
}

.cx-btn.is-demo .cx-btn__trail--a {
  animation: cx-trail-a-loop 2s ease-out infinite;
}

.cx-btn.is-demo .cx-btn__trail--b {
  animation: cx-trail-b-loop 2s ease-out infinite;
}

@media (prefers-reduced-motion: reduce) {
  .cx-btn,
  .cx-btn.is-demo,
  .cx-btn__arrow--a,
  .cx-btn__arrow--b,
  .cx-btn.is-demo .cx-btn__arrow--a,
  .cx-btn.is-demo .cx-btn__arrow--b {
    animation: none !important;
    transition: none !important;
  }
  .cx-btn {
    transform: scale(1) !important;
    border-color: #17141a !important;
  }
  .cx-btn__arrow--a {
    opacity: 1 !important;
    transform: rotate(45deg) translateX(0) !important;
  }
  .cx-btn__arrow--b {
    opacity: 0 !important;
    transform: rotate(45deg) translateX(-16px) !important;
  }
  .cx-btn__trail,
  .cx-btn:hover .cx-btn__trail,
  .cx-btn.is-demo .cx-btn__trail {
    animation: none !important;
    opacity: 0 !important;
  }
}

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

export interface CircleArrowHoverProps {
  duration?: string;
  easing?: string;
  color?: string;
}

export default function CircleArrowHover({
  duration = "280ms",
  easing = "cubic-bezier(.34, 1.56, .64, 1)",
  color = "#2f6df6",
}: CircleArrowHoverProps) {
  const style = { "--duration": duration, "--easing": easing, "--color": color } as CSSProperties;
  return (
    <a className={styles.btn} href="#" aria-label="Next" style={style}>
      <span className={`${styles.arrow} ${styles.a}`} />
      <span className={`${styles.arrow} ${styles.b}`} />
      <span className={`${styles.trail} ${styles.trailA}`} aria-hidden="true" />
      <span className={`${styles.trail} ${styles.trailB}`} aria-hidden="true" />
    </a>
  );
}