02Feature card grid — cards revealing in order from a visible-ratio value

<main class="stage" id="stage">
  <div class="grid is-demo">
    <article class="card" style="--i:0">
      <p class="card__badge">01</p>
      <h3 class="card__title">Fast install</h3>
      <p class="card__desc">Done with one line of script</p>
    </article>
    <article class="card" style="--i:1">
      <p class="card__badge">02</p>
      <h3 class="card__title">Real-time sync</h3>
      <p class="card__desc">Instantly reflected on every device</p>
    </article>
    <article class="card" style="--i:2">
      <p class="card__badge">03</p>
      <h3 class="card__title">Secure backup</h3>
      <p class="card__desc">Saved automatically every day</p>
    </article>
    <article class="card" style="--i:3">
      <p class="card__badge">04</p>
      <h3 class="card__title">Easy sharing</h3>
      <p class="card__desc">Invite with a single link</p>
    </article>
  </div>
</main>

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

// 계산 상수: 카드 순서 값(--i) × 간격 상수(스태거 간격)
$stagger-step: 120ms;

$duration: $dur-enter;
$easing: $ease-out;
$color: $subject-blue-deep;

@include stage($stage-yellow);

.grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: $sp-3;
  width: 100%;
  max-width: 380px;
}

.card {
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  gap: $sp-1;
  padding: $sp-4;
  border-radius: $r-card;
  background: $stage-paper;
  box-shadow: $shadow-press;
  opacity: 0;
  transform: translateY(14px);
}

.card__badge {
  margin: 0;
  align-self: flex-start;
  padding: $sp-1 $sp-2;
  border-radius: $r-xs;
  background: rgba($color, .12);
  color: $color;
  font-weight: 700;
  font-size: 10px;
  line-height: 1.4;
}

.card__title {
  margin: 0;
  color: $subject-ink;
  font-weight: 600;
  font-size: 13px;
  line-height: 1.3;
}

.card__desc {
  margin: 0;
  color: rgba($subject-ink, .72);
  font-weight: 400;
  font-size: 11px;
  line-height: 1.5;
}

.is-demo .card {
  animation: card-in $duration $easing both;
  animation-delay: calc(var(--i) * #{$stagger-step});
}

@keyframes card-in {
  0% { opacity: 0; transform: translateY(14px); }
  100% { opacity: 1; transform: translateY(0); }
}

@media (max-width: 340px) {
  .grid { gap: $sp-2; max-width: 280px; }
  .card { padding: $sp-2 $sp-3; gap: 0; }
  .card__title { font-size: 12px; }
  .card__desc { font-size: 10px; }
}

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

.grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  width: 100%;
  max-width: 380px;
}

.card {
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 16px;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  opacity: 0;
  transform: translateY(14px);
}

.card__badge {
  margin: 0;
  align-self: flex-start;
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(10, 79, 232, 0.12);
  color: #0a4fe8;
  font-weight: 700;
  font-size: 10px;
  line-height: 1.4;
}

.card__title {
  margin: 0;
  color: #17141a;
  font-weight: 600;
  font-size: 13px;
  line-height: 1.3;
}

.card__desc {
  margin: 0;
  color: rgba(23, 20, 26, 0.72);
  font-weight: 400;
  font-size: 11px;
  line-height: 1.5;
}

.is-demo .card {
  animation: card-in 600ms ease-out both;
  animation-delay: calc(var(--i) * 120ms);
}

@keyframes card-in {
  0% {
    opacity: 0;
    transform: translateY(14px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}
@media (max-width: 340px) {
  .grid {
    gap: 8px;
    max-width: 280px;
  }
  .card {
    padding: 8px 12px;
    gap: 0;
  }
  .card__title {
    font-size: 12px;
  }
  .card__desc {
    font-size: 10px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .is-demo .card {
    animation: none;
    opacity: 1;
    transform: none;
  }
}

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

// 카드 순서 값(--i)에 간격 상수(스태거 간격)를 곱한 값을 animation-delay 로 써서 카드가 순서대로 뜬다.
// 계산 겹: 카드 순서 값(--i) × 간격 상수 -> animation-delay. 리스너 없음(자동 재생).
type Vars = CSSProperties & { "--i"?: number };

const FEATURES = [
  { badge: "01", title: "빠른 설치", desc: "스크립트 한 줄로 끝" },
  { badge: "02", title: "실시간 동기화", desc: "모든 기기에 즉시 반영" },
  { badge: "03", title: "안전한 백업", desc: "매일 자동으로 저장" },
  { badge: "04", title: "간편한 공유", desc: "링크 하나로 초대" },
];

export default function FeatureGrid() {
  return (
    <main className={styles.stage}>
      <div className={`${styles.grid} ${styles["is-demo"]}`}>
        {FEATURES.map((item, i) => (
          <article
            key={item.badge}
            className={styles.card}
            style={{ "--i": i } as Vars}
          >
            <p className={styles.card__badge}>{item.badge}</p>
            <h3 className={styles.card__title}>{item.title}</h3>
            <p className={styles.card__desc}>{item.desc}</p>
          </article>
        ))}
      </div>
    </main>
  );
}