04Corner bracket frame

<main class="stage">
  <article class="card is-demo" tabindex="0">
    <span class="corner corner--tl" aria-hidden="true"></span>
    <span class="corner corner--tr" aria-hidden="true"></span>
    <span class="corner corner--bl" aria-hidden="true"></span>
    <span class="corner corner--br" aria-hidden="true"></span>
    <span class="card__media" aria-hidden="true"></span>
    <div class="card__body">
      <h3 class="card__title">Autumn collection</h3>
    </div>
  </article>
</main>

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

$duration: $dur-quick;                                  // 브래킷이 자라는 시간
$easing: $ease-out;
$color: $subject-blue;                                   // 브래킷 색

@include stage($stage-paper);
.stage { padding: clamp(8px, 2.4vw, 16px); }

.card {
  position: relative;
  width: min(150px, 48vw);
  aspect-ratio: 4 / 3;
  border-radius: $r-card;
  overflow: hidden;
  background: $stage-ink;
  outline: none;
  cursor: pointer;
}
.card__media {
  position: absolute; inset: 0;
  background: linear-gradient(155deg, $color 0%, $stage-ink 100%);
}
.card__body {
  position: absolute; left: 0; right: 0; bottom: 0;
  padding: $sp-2 $sp-3;
}
.card__title { margin: 0; font-weight: 700; font-size: clamp(11px, 3.2vw, 13px); line-height: 1.3; font-family: inherit; color: $stage-paper; }

.corner {
  position: absolute;
  width: $sp-4;
  height: $sp-4;
  border: 2px solid $color;
  opacity: 0;
  z-index: 2;
  transition: transform $duration $easing, opacity $duration $easing;
}
.corner--tl { top: $sp-2; left: $sp-2; border-right: none; border-bottom: none; transform: translate($sp-2, $sp-2); }
.corner--tr { top: $sp-2; right: $sp-2; border-left: none; border-bottom: none; transform: translate(-$sp-2, $sp-2); }
.corner--bl { bottom: $sp-2; left: $sp-2; border-right: none; border-top: none; transform: translate($sp-2, -$sp-2); }
.corner--br { bottom: $sp-2; right: $sp-2; border-left: none; border-top: none; transform: translate(-$sp-2, -$sp-2); }

.card:hover .corner,
.card:focus-visible .corner,
.card:active .corner {
  opacity: 1;
  transform: translate(0, 0);
}
.card.is-demo .corner { animation: frame-loop $dur-loop $easing infinite; }
@keyframes frame-loop {
  0%, 15%  { opacity: 0; }
  45%, 75% { opacity: 1; transform: translate(0, 0); }
  100%     { opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .corner { transition: none; }
  .card.is-demo .corner { animation: none; opacity: 1; transform: translate(0, 0); }
}

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);
}

.stage {
  padding: clamp(8px, 2.4vw, 16px);
}

.card {
  position: relative;
  width: min(150px, 48vw);
  aspect-ratio: 4/3;
  border-radius: 16px;
  overflow: hidden;
  background: #17141a;
  outline: none;
  cursor: pointer;
}

.card__media {
  position: absolute;
  inset: 0;
  background: linear-gradient(155deg, #2f6df6 0%, #17141a 100%);
}

.card__body {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 8px 12px;
}

.card__title {
  margin: 0;
  font-weight: 700;
  font-size: clamp(11px, 3.2vw, 13px);
  line-height: 1.3;
  font-family: inherit;
  color: #ffffff;
}

.corner {
  position: absolute;
  width: 16px;
  height: 16px;
  border: 2px solid #2f6df6;
  opacity: 0;
  z-index: 2;
  transition: transform 220ms ease-out, opacity 220ms ease-out;
}

.corner--tl {
  top: 8px;
  left: 8px;
  border-right: none;
  border-bottom: none;
  transform: translate(8px, 8px);
}

.corner--tr {
  top: 8px;
  right: 8px;
  border-left: none;
  border-bottom: none;
  transform: translate(-8px, 8px);
}

.corner--bl {
  bottom: 8px;
  left: 8px;
  border-right: none;
  border-top: none;
  transform: translate(8px, -8px);
}

.corner--br {
  bottom: 8px;
  right: 8px;
  border-left: none;
  border-top: none;
  transform: translate(-8px, -8px);
}

.card:hover .corner,
.card:focus-visible .corner,
.card:active .corner {
  opacity: 1;
  transform: translate(0, 0);
}

.card.is-demo .corner {
  animation: frame-loop 2s ease-out infinite;
}

@keyframes frame-loop {
  0%, 15% {
    opacity: 0;
  }
  45%, 75% {
    opacity: 1;
    transform: translate(0, 0);
  }
  100% {
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .corner {
    transition: none;
  }
  .card.is-demo .corner {
    animation: none;
    opacity: 1;
    transform: translate(0, 0);
  }
}

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

export type CornerFrameCardProps = {
  title: string;
  /** 브래킷이 자라는 시간 (기본 220ms) */
  duration?: number;
  easing?: string;
  /** 브래킷 색 */
  color?: string;
};

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

export default function CornerFrameCard({
  title,
  duration = 220,
  easing = "ease-out",
  color = "#2f6df6",
}: CornerFrameCardProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <article className={styles.card} style={vars} tabIndex={0}>
      <span className={`${styles.corner} ${styles.tl}`} aria-hidden="true" />
      <span className={`${styles.corner} ${styles.tr}`} aria-hidden="true" />
      <span className={`${styles.corner} ${styles.bl}`} aria-hidden="true" />
      <span className={`${styles.corner} ${styles.br}`} aria-hidden="true" />
      <span className={styles.media} aria-hidden="true" />
      <div className={styles.body}>
        <h3 className={styles.title}>{title}</h3>
      </div>
    </article>
  );
}