08Grainy dark footer

<main class="stage">
  <footer class="footer-a">
    <div class="footer-a__col">
      <p class="footer-a__label">Product</p>
      <p class="footer-a__link">Features</p>
    </div>
    <div class="footer-a__col">
      <p class="footer-a__label">Company</p>
      <p class="footer-a__link">About</p>
    </div>
  </footer>
</main>

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

$duration: $dur-loop;
$easing: steps(6, jump-none);  // 그레인이 부드럽게 흐르지 않고 프레임마다 뚝뚝 튄다
$color: $subject-cream;

@include stage($stage-paper);

.footer-a {
  position: relative;
  overflow: hidden;
  box-sizing: border-box;
  width: clamp(260px, 88vw, 400px);
  border-radius: $r-card;
  padding: $sp-6;
  background: $stage-ink;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: $sp-4;
}
// 필름 그레인 — steps() 로 프레임마다 자리를 바꿔 지지직거리는 질감을 만든다 (이 항목의 유일한 애니메이션)
.footer-a::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .45;
  mix-blend-mode: overlay;
  background-image:
    radial-gradient(rgba($color, .7) .6px, transparent .6px),
    radial-gradient(rgba($stage-ink, .7) .6px, transparent .6px);
  background-size: 3px 3px, 5px 5px;
  animation: grainJump $duration $easing infinite;
}
.footer-a__col { position: relative; z-index: 1; border-radius: $r-sm; background: rgba($stage-paper, .05); padding: $sp-3; display: flex; flex-direction: column; gap: $sp-1; }
.footer-a__label { margin: 0; color: rgba($stage-paper, .5); font: 700 clamp(9.5px, 2.2vw, 10.5px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif; text-transform: uppercase; letter-spacing: .06em; }
.footer-a__link { margin: 0; color: $stage-paper; font-weight: 600; font-size: clamp(11px, 2.6vw, 12px); line-height: 1.4; }

@keyframes grainJump {
  0%   { background-position: 0 0, 0 0; }
  20%  { background-position: -6px 4px, 3px -5px; }
  40%  { background-position: 5px -3px, -4px 6px; }
  60%  { background-position: -3px -6px, 6px 2px; }
  80%  { background-position: 4px 5px, -5px -3px; }
  100% { background-position: 0 0, 0 0; }
}

@media (prefers-reduced-motion: reduce) {
  .footer-a::before { animation: none; }
}

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);
}

.footer-a {
  position: relative;
  overflow: hidden;
  box-sizing: border-box;
  width: clamp(260px, 88vw, 400px);
  border-radius: 16px;
  padding: 24px;
  background: #17141a;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.footer-a::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.45;
  mix-blend-mode: overlay;
  background-image: radial-gradient(rgba(255, 247, 230, 0.7) 0.6px, transparent 0.6px), radial-gradient(rgba(23, 20, 26, 0.7) 0.6px, transparent 0.6px);
  background-size: 3px 3px, 5px 5px;
  animation: grainJump 2s steps(6, jump-none) infinite;
}

.footer-a__col {
  position: relative;
  z-index: 1;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.05);
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.footer-a__label {
  margin: 0;
  color: rgba(255, 255, 255, 0.5);
  font: 700 clamp(9.5px, 2.2vw, 10.5px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.footer-a__link {
  margin: 0;
  color: #ffffff;
  font-weight: 600;
  font-size: clamp(11px, 2.6vw, 12px);
  line-height: 1.4;
}

@keyframes grainJump {
  0% {
    background-position: 0 0, 0 0;
  }
  20% {
    background-position: -6px 4px, 3px -5px;
  }
  40% {
    background-position: 5px -3px, -4px 6px;
  }
  60% {
    background-position: -3px -6px, 6px 2px;
  }
  80% {
    background-position: 4px 5px, -5px -3px;
  }
  100% {
    background-position: 0 0, 0 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .footer-a::before {
    animation: none;
  }
}

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

export type AuroraFooterProps = {
  columns?: { label: string; link: string }[];
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function AuroraFooter({
  columns = [
    { label: "Product", link: "Features" },
    { label: "Company", link: "About" },
  ],
  duration = 2000,
  easing = "steps(6, jump-none)",
  color = "#fff7e6",
}: AuroraFooterProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <footer className={styles.footer} style={vars}>
      {columns.map((col) => (
        <div key={col.label} className={styles.col}>
          <p className={styles.label}>{col.label}</p>
          <p className={styles.link}>{col.link}</p>
        </div>
      ))}
    </footer>
  );
}