09Gradient buttons, glow focus

<main class="stage">
  <form class="bi-a is-demo">
    <input class="bi-a__input" type="email" placeholder="Email address" readonly>
    <button class="bi-a__btn" type="button">Sign up</button>
  </form>
</main>

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

$duration: $dur-loop;
$easing: $ease-out;
$color: $stage-yellow;

@include stage($stage-ink);

.bi-a { display: flex; flex-direction: column; gap: $sp-4; width: clamp(220px, 78vw, 320px); }
.bi-a__input {
  border: 0;
  border-radius: $r-control;
  padding: $sp-3 $sp-4;
  background: rgba($stage-paper, .06);
  color: $stage-paper;
  font: 500 clamp(12px, 3vw, 13.5px)/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  box-shadow: 0 0 0 2px rgba($subject-blue, .55), 0 0 16px rgba($stage-orange, .45);
}
.bi-a__input::placeholder { color: rgba($stage-paper, .4); }
// 버튼 안 그라디언트는 호버(.is-demo 로 강제 발동)에만 흐른다 — background-position 만 바뀐다
.bi-a__btn {
  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;
  background: linear-gradient(120deg, $color, $stage-orange, $subject-blue, $color);
  background-size: 260% 100%;
  background-position: 0% 50%;
}
.is-demo .bi-a__btn,
.bi-a__btn:hover,
.bi-a__btn:focus-visible {
  animation: shift $duration $easing infinite;
}

@keyframes shift { 0% { background-position: 0% 50%; } 50% { background-position: 100% 50%; } 100% { background-position: 0% 50%; } }

@media (prefers-reduced-motion: reduce) {
  .is-demo .bi-a__btn, .bi-a__btn:hover, .bi-a__btn:focus-visible { 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-a {
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: clamp(220px, 78vw, 320px);
}

.bi-a__input {
  border: 0;
  border-radius: 12px;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.06);
  color: #ffffff;
  font: 500 clamp(12px, 3vw, 13.5px)/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  box-shadow: 0 0 0 2px rgba(47, 109, 246, 0.55), 0 0 16px rgba(255, 77, 31, 0.45);
}

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

.bi-a__btn {
  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;
  background: linear-gradient(120deg, #ffd23f, #ff4d1f, #2f6df6, #ffd23f);
  background-size: 260% 100%;
  background-position: 0% 50%;
}

.is-demo .bi-a__btn,
.bi-a__btn:hover,
.bi-a__btn:focus-visible {
  animation: shift 2s ease-out infinite;
}

@keyframes shift {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}
@media (prefers-reduced-motion: reduce) {
  .is-demo .bi-a__btn, .bi-a__btn:hover, .bi-a__btn:focus-visible {
    animation: none;
  }
}

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

export type AuroraButtonsInputsProps = {
  placeholder?: string;
  cta?: string;
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function AuroraButtonsInputs({
  placeholder = "Email address",
  cta = "Sign up",
  duration = 2000,
  easing = "ease-out",
  color = "#ffd23f",
}: AuroraButtonsInputsProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  const [hover, setHover] = useState(false);

  return (
    <form className={styles.form} style={vars} onSubmit={(e: { preventDefault: () => void }) => e.preventDefault()}>
      <input className={styles.input} type="email" placeholder={placeholder} />
      <button
        type="submit"
        className={`${styles.btn} ${hover ? styles.active : ""}`}
        onMouseEnter={() => setHover(true)}
        onMouseLeave={() => setHover(false)}
      >
        {cta}
      </button>
    </form>
  );
}