:root {
  --primary-blue: #003366;
  --secondary-blue: #0066CC;
  --text-dark: #2C2C2C;
  --text-light: #666666;
  --background-white: #FFFFFF;
  --background-light: #F8F9FA;
  --accent-gold: #D4AF37;
  --border-light: #E1E5E9;
  --hover-blue: #E6F2FF;
  --gradient-primary: linear-gradient(135deg, #003366 0%, #0066CC 100%);
  --gradient-overlay: linear-gradient(45deg, rgba(0, 51, 102, 0.9), rgba(0, 102, 204, 0.8));
  --shadow-soft: 0 10px 40px rgba(0, 51, 102, 0.1);
  --shadow-hover: 0 20px 60px rgba(0, 51, 102, 0.2);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "ヒラギノ角ゴ ProN W3", "Meiryo", "メイリオ", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: var(--text-dark);
  background: var(--background-light);
}

#container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ヘッダースタイル */
.site-header {
  background: var(--background-white);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
}

#headernav {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

.logo img {
  height: 50px;
  width: auto;
}

#headernav nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

#headernav nav a {
  text-decoration: none;
  color: var(--text-dark);
  font-weight: 500;
  transition: color 0.3s ease;
}

#headernav nav a:hover {
  color: var(--secondary-blue);
}

/* ハンバーガーメニュー */
#menu-icon {
  display: none;
  flex-direction: column;
  justify-content: space-around;
  width: 30px;
  height: 24px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

#menu-icon span {
  width: 100%;
  height: 3px;
  background: var(--text-dark);
  border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

/* ページヘッダー */
.page-header {
  background: var(--gradient-primary);
  color: white;
  text-align: center;
  padding: 120px 2rem 60px;
  margin-top: 80px;
}

.page-header h1 {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
}

.icon-accent {
  color: var(--accent-gold);
}

.page-header p {
  font-size: 1.2rem;
  opacity: 0.9;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* メインコンテンツ */
.main-content {
  flex: 1;
  padding: 4rem 0;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 3rem;
  color: var(--primary-blue);
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: var(--accent-gold);
  margin: 1rem auto;
  border-radius: 2px;
}

/* プレミアムスライドショー */
.slideshow-container {
  position: relative;
  width: 100%;
  max-width: 1400px;
  margin: 2rem auto;
  height: 600px;
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow-soft);
  background: var(--background-white);
}

/* スライドのスタイル (JSの変更に対応) */
.slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  background: var(--gradient-primary);
  transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  opacity: 0;
  transform: translateX(100%);
  /* デフォルトは右側へ隠す */
}

.slide.active {
  opacity: 1;
  transform: translateX(0);
  z-index: 2;
}

.slide.is-exiting-forward {
  transform: translateX(-100%);
  /* 前に進む時、古いスライドは左へ消える */
}

.slide.is-exiting-backward {
  transform: translateX(100%);
  /* 後ろに戻る時、古いスライドは右へ消える */
}

.slide-content {
  display: flex;
  width: 100%;
  height: 100%;
  align-items: center;
  position: relative;
}

.slide-image {
  flex: 1;
  height: 100%;
  position: relative;
  overflow: hidden;
}

.slide-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.8s ease;
}

.slide.active .slide-image img {
  transform: scale(1.05);
}

.slide-info {
  flex: 1;
  padding: 4rem;
  color: white;
  position: relative;
  z-index: 3;
}

.slide-category {
  display: inline-block;
  background: var(--accent-gold);
  color: var(--primary-blue);
  padding: 0.5rem 1.2rem;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  letter-spacing: 0.05em;
}

.slide-title {
  font-size: 3rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1.5rem;
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1) 0.2s;
}

.slide.active .slide-title {
  opacity: 1;
  transform: translateY(0);
}

.slide-author {
  font-size: 1.3rem;
  opacity: 0.9;
  margin-bottom: 2rem;
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1) 0.4s;
}

.slide.active .slide-author {
  opacity: 0.9;
  transform: translateY(0);
}

.slide-description {
  font-size: 1.1rem;
  line-height: 1.6;
  margin-bottom: 2.5rem;
  opacity: 0.85;
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1) 0.6s;
}

.slide.active .slide-description {
  opacity: 0.85;
  transform: translateY(0);
}

.slide-price {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-gold);
  margin-bottom: 2rem;
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1) 0.8s;
}

.slide.active .slide-price {
  opacity: 1;
  transform: translateY(0);
}

.slide-actions {
  display: flex;
  gap: 1rem;
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1) 1s;
}

.slide.active .slide-actions {
  opacity: 1;
  transform: translateY(0);
}

.btn {
  padding: 1rem 2rem;
  border: none;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--accent-gold);
  color: var(--primary-blue);
}

.btn-primary:hover {
  background: #F4C430;
  transform: translateY(-2px);
  box-shadow: 0 10px 25px rgba(212, 175, 55, 0.4);
}

.btn-secondary {
  background: transparent;
  color: white;
  border: 2px solid white;
}

.btn-secondary:hover {
  background: white;
  color: var(--primary-blue);
  transform: translateY(-2px);
}

/* ナビゲーションコントロール */
.nav-controls {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 1rem;
  z-index: 10;
}

.nav-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.5);
  cursor: pointer;
  transition: all 0.3s ease;
  border: 2px solid transparent;
}

.nav-dot.active {
  background: var(--accent-gold);
  transform: scale(1.2);
  box-shadow: 0 0 0 3px rgba(212, 175, 55, 0.3);
}

.nav-dot:hover {
  background: rgba(255, 255, 255, 0.8);
  transform: scale(1.1);
}

/* 矢印ナビゲーション */
.nav-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255, 255, 255, 0.2);
  border: none;
  width: 60px;
  height: 60px;
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.3s ease;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(10px);
}

.nav-arrow:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: translateY(-50%) scale(1.1);
}

.nav-arrow.prev {
  left: 2rem;
}

.nav-arrow.next {
  right: 2rem;
}

.nav-arrow::after {
  content: '';
  width: 12px;
  height: 12px;
  border: 3px solid white;
  border-left: none;
  border-bottom: none;
  transform: rotate(45deg);
}

.nav-arrow.prev::after {
  transform: rotate(-135deg);
}

/* プログレスバー */
.progress-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  height: 4px;
  background: var(--accent-gold);
  transition: width 0.1s ease;
  z-index: 10;
}

/* フッターナビゲーションエリア */
#footer_navi {
  background: var(--primary-blue);
  color: white;
  padding: 4rem 0;
}

.daisosha_service h3 {
  font-size: 2rem;
  margin-bottom: 2rem;
  text-align: center;
}

.service-button-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.cta-button-service {
  display: flex;
  align-items: center;
  padding: 1.5rem;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  text-decoration: none;
  color: white;
  transition: all 0.3s ease;
  border: 2px solid transparent;
}

.cta-button-service:hover {
  background: rgba(255, 255, 255, 0.2);
  border-color: var(--accent-gold);
  transform: translateY(-2px);
}

.button-icon {
  margin-right: 1rem;
  font-size: 1.5rem;
}

.arrow {
  margin-left: auto;
  font-weight: bold;
}

/* フッター */
#footer_wrapper {
  background: var(--text-dark);
  color: white;
  padding: 2rem 0;
}

#footer ul {
  list-style: none;
  text-align: center;
}

#footer li {
  margin: 0.5rem 0;
}

#footer a {
  color: white;
  text-decoration: none;
  transition: color 0.3s ease;
}

#footer a:hover {
  color: var(--accent-gold);
}

.copyright {
  margin-top: 2rem !important;
  padding-top: 2rem;
  border-top: 1px solid #555;
  font-size: 0.9rem;
  opacity: 0.8;
}

/* ページトップボタン */
.page-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 60px;
  height: 60px;
  background: var(--accent-gold);
  color: var(--primary-blue);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  font-size: 1.5rem;
  box-shadow: 0 4px 15px rgba(212, 175, 55, 0.3);
  transition: all 0.3s ease;
  z-index: 1000;
}

.page-top:hover {
  background: #F4C430;
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(212, 175, 55, 0.4);
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
  #headernav nav {
    display: none;
    /* デフォルトは非表示 */
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--background-white);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    padding: 1rem 0;
  }

  /* JSで .is-open クラスが付与されたら表示 */
  .site-header.is-open #headernav nav {
    display: block;
  }

  #headernav nav ul {
    flex-direction: column;
    gap: 0;
  }

  #headernav nav li {
    border-bottom: 1px solid var(--border-light);
  }

  #headernav nav a {
    display: block;
    padding: 1rem 2rem;
  }

  #menu-icon {
    display: flex;
    /* スマホ表示の時だけ表示 */
  }

  /* ハンバーガーアイコンのX印への変形 (JSの .is-open クラスに対応) */
  .site-header.is-open #menu-icon .first {
    transform: translateY(9px) rotate(45deg);
  }

  .site-header.is-open #menu-icon .second {
    opacity: 0;
  }

  .site-header.is-open #menu-icon .third {
    transform: translateY(-9px) rotate(-45deg);
  }

  .page-header h1 {
    font-size: 2rem;
    flex-direction: column;
    gap: 0.5rem;
  }

  .page-header {
    padding: 100px 1rem 40px;
  }

  .slideshow-container {
    height: 500px;
    margin: 1rem;
    border-radius: 16px;
  }

  .slide-content {
    flex-direction: column;
  }

  .slide-image {
    height: 50%;
  }

  .slide-info {
    padding: 2rem;
    height: 50%;
    display: flex;
    flex-direction: column;
    justify-content: center;
  }

  .slide-title {
    font-size: 1.8rem;
    margin-bottom: 1rem;
  }

  .slide-author {
    font-size: 1rem;
    margin-bottom: 1rem;
  }

  .slide-description {
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
  }

  .slide-price {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
  }

  .slide-actions {
    flex-direction: column;
    gap: 0.5rem;
  }

  .btn {
    padding: 0.8rem 1.5rem;
    font-size: 0.9rem;
  }

  .nav-arrow {
    width: 50px;
    height: 50px;
  }

  .nav-arrow.prev {
    left: 1rem;
  }

  .nav-arrow.next {
    right: 1rem;
  }

  .service-button-list {
    grid-template-columns: 1fr;
  }

  .container {
    padding: 0 1rem;
  }
}

/* アクセシビリティ */
@media (prefers-reduced-motion: reduce) {

  .slide,
  .slide-title,
  .slide-author,
  .slide-description,
  .slide-price,
  .slide-actions,
  .page-top,
  .cta-button-service,
  .book-card,
  .book-cover img {
    transition: none !important;
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* フォーカス表示 */
.nav-dot:focus,
.nav-arrow:focus,
.btn:focus,
#headernav nav a:focus,
.cta-button-service:focus {
  outline: 3px solid var(--accent-gold);
  outline-offset: 2px;
}

/* =============================================== */
/* すべての電子書籍セクションのスタイル (修正・追加箇所) */
/* =============================================== */

.bookstore-section {
  padding-top: 2rem;
}

/* --- 1. 書籍リスト全体のグリッド設定 --- */
.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

/* --- 2. 各書籍カードの基本スタイル --- */
.book-card {
  background: var(--background-white);
  border-radius: 12px;
  box-shadow: var(--shadow-soft);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.book-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}

/* --- 3. 書籍カバー画像のサイズを統一 --- */
.book-cover {
  aspect-ratio: 2 / 3;
  overflow: hidden;
  position: relative;
  background-color: #eee;
}

.book-cover img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.book-card:hover .book-cover img {
  transform: scale(1.05);
}

/* --- 4. カード内の情報エリアを整理 --- */
.book-info {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.book-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-blue);
  line-height: 1.4;
  min-height: calc(1.25rem * 1.4 * 2);
  /* 2行分の高さを確保 */
}

.book-author,
.book-price {
  font-size: 0.9rem;
  color: var(--text-light);
  margin-top: 0.5rem;
}

.book-description {
  margin-top: 1rem;
  font-size: 0.95rem;
  color: var(--text-dark);
  flex-grow: 1;
}

/* --- 5. リンクボタンをカードの最下部に揃える --- */
.external-links {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.link-button {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
  text-align: center;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.link-button .fab,
.link-button .fas {
  margin-right: 0.5rem;
}

.amazon-link {
  background-color: #FF9900;
  color: white;
}

.amazon-link:hover {
  background-color: #E68A00;
}

.detail-link {
  background-color: var(--secondary-blue);
  color: white;
}

.detail-link:hover {
  background-color: var(--primary-blue);
}

.buy-button,
.eslite-link {
  background-color: var(--text-dark);
  color: white;
}

.buy-button:hover,
.eslite-link:hover {
  background-color: #000;
}

.purchase-note {
  font-size: 0.8rem;
  color: var(--text-light);
  text-align: center;
  margin-top: 0.5rem;
}