@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;700&family=Zen+Kaku+Gothic+New:wght@500;700;900&display=swap');

:root {
  --background: 0 0% 100%;
  --foreground: 222.2 84% 4.9%;
  --primary: 199 89% 48%;
  --border: 214.3 31.8% 91.4%;
  --radius: 0.5rem;
}

body {
  font-family: 'Noto Sans JP', sans-serif;
  color: hsl(var(--foreground));
  background-color: hsl(var(--background));
  -webkit-font-smoothing: antialiased;
}

.font-heading {
  font-family: 'Zen Kaku Gothic New', 'Noto Sans JP', sans-serif;
}

/* ---------------------------------------------
 * 背景フェードイン・フェードアウトスライダー (4枚)
 * --------------------------------------------- */
.hero-slider-bg {
  position: absolute;
  inset: 0;
  z-index: -20;
}

.hero-slide {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0;
  animation: heroFade 16s infinite ease-in-out;
}

.hero-slide:nth-child(1) { animation-delay: 0s; }
.hero-slide:nth-child(2) { animation-delay: 4s; }
.hero-slide:nth-child(3) { animation-delay: 8s; }
.hero-slide:nth-child(4) { animation-delay: 12s; }

@keyframes heroFade {
  0% { opacity: 0; }
  6.25% { opacity: 1; }
  25% { opacity: 1; }
  31.25% { opacity: 0; }
  100% { opacity: 0; }
}

/* ---------------------------------------------
 * ページTOPへ戻るボタン
 * --------------------------------------------- */
#scroll-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 40;
  display: flex;
  height: 48px;
  width: 48px;
  align-items: center;
  justify-content: center;
  border-radius: 9999px;
  background-color: hsl(var(--primary));
  color: #fff;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
  transform: translateY(10px);
}

#scroll-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#scroll-to-top:hover {
  opacity: 0.9;
  transform: translateY(-3px);
}

/* ---------------------------------------------
 * フォーム要素
 * --------------------------------------------- */
.form-input {
  width: 100%;
  border-radius: calc(var(--radius) * 0.8);
  border: 1px solid hsl(var(--border));
  background-color: #fff;
  padding: 0.625rem 0.875rem;
  font-size: 0.875rem;
  color: hsl(var(--foreground));
  transition: border-color 0.2s;
}

.form-input:focus {
  outline: none;
  border-color: hsl(var(--primary));
  box-shadow: 0 0 0 2px hsl(var(--primary) / 0.2);
}