09Chrome buttons, holographic focus

<main class="stage">
  <form class="bi-c is-demo">
    <input class="bi-c__input" type="email" placeholder="Email address" readonly>
    <button class="bi-c__btn" type="button">Sign up</button>
  </form>
</main>

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

$duration: $dur-loop;
$easing: $ease-out;
$color: $subject-cream;

@include stage($stage-ink);

.bi-c { display: flex; flex-direction: column; gap: $sp-4; width: clamp(220px, 78vw, 320px); }
.bi-c__input {
  border: 0;
  border-radius: $r-control;
  padding: $sp-3 $sp-4;
  background: rgba($stage-paper, .06);
  color: $stage-paper;
  font-weight: 500;
  font-size: clamp(12px, 3vw, 13.5px);
  line-height: 1.3;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  box-shadow: 0 0 0 2px rgba($subject-blue, .5), 0 0 16px rgba($stage-yellow, .4), 0 0 22px rgba($stage-orange, .3);
}
.bi-c__input::placeholder { color: rgba($stage-paper, .4); }
// 버튼 — 위에 있던 스펙큘러 하이라이트가 눌리면 아래로 뒤집힌다 (유일한 애니메이션, .is-demo 로 강제 발동)
.bi-c__btn {
  position: relative;
  overflow: hidden;
  align-self: flex-start;
  border: 0;
  border-radius: $r-control;
  padding: $sp-3 $sp-6;
  color: $stage-ink;
  font-weight: 700;
  font-size: clamp(12px, 3vw, 13.5px);
  line-height: 1;
  font-family: inherit;
  background: linear-gradient(180deg, $color, $stage-paper 55%, rgba($stage-paper, .85));
}
.bi-c__btn::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba($stage-paper, .9), transparent 55%);
}
.is-demo .bi-c__btn::after,
.bi-c__btn:hover::after,
.bi-c__btn:focus-visible::after {
  animation: pressFlip $duration $easing infinite;
}

@keyframes pressFlip {
  0%, 40%   { transform: translateY(0); opacity: 1; }
  50%, 60%  { transform: translateY(100%); opacity: .7; }
  70%, 100% { transform: translateY(0); opacity: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .is-demo .bi-c__btn::after, .bi-c__btn:hover::after, .bi-c__btn:focus-visible::after { animation: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.bi-c {
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: clamp(220px, 78vw, 320px);
}

.bi-c__input {
  border: 0;
  border-radius: 12px;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.06);
  color: #ffffff;
  font-weight: 500;
  font-size: clamp(12px, 3vw, 13.5px);
  line-height: 1.3;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  box-shadow: 0 0 0 2px rgba(47, 109, 246, 0.5), 0 0 16px rgba(255, 210, 63, 0.4), 0 0 22px rgba(255, 77, 31, 0.3);
}

.bi-c__input::placeholder {
  color: rgba(255, 255, 255, 0.4);
}

.bi-c__btn {
  position: relative;
  overflow: hidden;
  align-self: flex-start;
  border: 0;
  border-radius: 12px;
  padding: 12px 24px;
  color: #17141a;
  font-weight: 700;
  font-size: clamp(12px, 3vw, 13.5px);
  line-height: 1;
  font-family: inherit;
  background: linear-gradient(180deg, #fff7e6, #ffffff 55%, rgba(255, 255, 255, 0.85));
}

.bi-c__btn::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.9), transparent 55%);
}

.is-demo .bi-c__btn::after,
.bi-c__btn:hover::after,
.bi-c__btn:focus-visible::after {
  animation: pressFlip 2s ease-out infinite;
}

@keyframes pressFlip {
  0%, 40% {
    transform: translateY(0);
    opacity: 1;
  }
  50%, 60% {
    transform: translateY(100%);
    opacity: 0.7;
  }
  70%, 100% {
    transform: translateY(0);
    opacity: 1;
  }
}
@media (prefers-reduced-motion: reduce) {
  .is-demo .bi-c__btn::after, .bi-c__btn:hover::after, .bi-c__btn:focus-visible::after {
    animation: none;
  }
}

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

export type ButtonsInputsChromeProps = {
  placeholder?: string;
  cta?: string;
  /** 한 주기(기본 2000ms) */
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function ButtonsInputsChrome({
  placeholder = "Email address",
  cta = "Sign up",
  duration = 2000,
  easing = "ease-out",
  color = "#fff7e6",
}: ButtonsInputsChromeProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <form className={styles.form} style={vars}>
      <input className={styles.input} type="email" placeholder={placeholder} readOnly />
      <button type="button" className={styles.btn}>{cta}</button>
    </form>
  );
}