/* ============================================
   WordFire! Web - スタイルシート
   ============================================ */

/* リセット & ベース */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* ブランドカラー */
  --brand-orange: #FF9933;
  --brand-purple: #A633F2;
  --brand-teal: #33BFD9;
  
  /* 背景色 */
  --bg-dark: #0D051A;
  --bg-surface: #1A0D33;
  --bg-surface-light: #2A1D43;
  
  /* テキスト色 */
  --text-primary: #FFFFFF;
  --text-secondary: rgba(255, 255, 255, 0.7);
  --text-tertiary: rgba(255, 255, 255, 0.5);
  
  /* スペーシング */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 4rem;
  --spacing-xl: 6rem;
  
  /* ボーダー */
  --border-radius: 24px;
  --border-radius-sm: 16px;
  
  /* シャドウ */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 32px rgba(255, 153, 51, 0.25);

  /* 固定ヘッダー高さ（JSで実寸に上書き） */
  --header-height: 80px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* ============================================
   ヘッダー & ナビゲーション
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(13, 5, 26, 0.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-sm) var(--spacing-md);
  max-width: 1200px;
  margin: 0 auto;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  text-decoration: none;
  transition: opacity 0.2s;
}

.nav-logo:hover {
  opacity: 0.8;
}

.flame-icon-small {
  width: 28px;
  height: 28px;
  object-fit: contain;
  animation: flicker 3s infinite;
}

.nav-title {
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

/* language switch */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding-left: var(--spacing-sm);
  border-left: 1px solid rgba(255, 255, 255, 0.12);
}

.lang-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  padding: 0.25rem 0.5rem;
  border-radius: 999px;
  transition: all 0.2s ease;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.02);
}

.lang-link:hover {
  color: var(--text-primary);
  border-color: rgba(255, 153, 51, 0.5);
}

.lang-link.active {
  color: var(--text-primary);
  border-color: rgba(255, 153, 51, 0.6);
  background: rgba(255, 153, 51, 0.12);
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.nav-link:hover {
  color: var(--text-primary);
}

/* ============================================
   ボタン
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--border-radius-sm);
  font-weight: 600;
  text-decoration: none;
  transition: all 0.3s;
  border: none;
  cursor: pointer;
  font-size: 1rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  color: var(--text-primary);
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(255, 153, 51, 0.4);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 2px solid rgba(255, 255, 255, 0.2);
}

.btn-outline:hover {
  border-color: var(--brand-purple);
  background: rgba(166, 51, 242, 0.1);
}

.btn-small {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

.btn-large {
  padding: 1rem 2rem;
  font-size: 1.125rem;
}

/* legal pages (privacy / terms / contact) */
.legal-page {
  padding: var(--spacing-xl) 0;
}

.legal-title {
  font-size: 2.5rem;
  font-weight: 900;
  margin-bottom: var(--spacing-md);
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.legal-card {
  background: var(--bg-surface-light);
  border-radius: var(--border-radius);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-sm);
}

.legal-paragraph {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: var(--spacing-sm);
}

.legal-actions {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
  margin-top: var(--spacing-md);
}

/* ============================================
   ヒーローセクション
   ============================================ */
.hero {
  position: relative;
  /* stacking context を作って背景レイヤーが前面に出ないようにする */
  z-index: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  /* 固定ヘッダーが被さらないように実寸ベースで確保 */
  padding-top: calc(var(--header-height) + 32px);
  overflow: hidden;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: -1;
  /* 背景レイヤーがクリック/ホバーを奪わないようにする */
  pointer-events: none;
}

/* 念のため、ヒーロー背景配下の全要素もクリック/ホバーを奪わないようにする */
.hero-background * {
  pointer-events: none;
}

.fire-effect {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(ellipse at center, rgba(255, 153, 51, 0.2) 0%, transparent 70%);
  animation: pulse 4s ease-in-out infinite;
  pointer-events: none;
}

.gradient-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(255, 153, 51, 0.15) 0%, rgba(166, 51, 242, 0.18) 50%, transparent 100%);
  pointer-events: none;
}

/* パーティクルコンテナ */
.particles-container {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
  pointer-events: none;
}

/* パーティクル */
.particle {
  position: absolute;
  bottom: -10px;
  width: 4px;
  height: 4px;
  background: radial-gradient(circle, rgba(255, 153, 51, 0.9) 0%, rgba(255, 200, 100, 0.6) 50%, transparent 100%);
  border-radius: 50%;
  box-shadow: 0 0 6px rgba(255, 153, 51, 0.8), 0 0 12px rgba(255, 153, 51, 0.4);
  animation: particle-rise linear infinite;
}

/* パーティクルのサイズバリエーション */
.particle.small {
  width: 2px;
  height: 2px;
  box-shadow: 0 0 4px rgba(255, 153, 51, 0.6);
}

.particle.medium {
  width: 4px;
  height: 4px;
}

.particle.large {
  width: 6px;
  height: 6px;
  box-shadow: 0 0 8px rgba(255, 153, 51, 0.9), 0 0 16px rgba(255, 153, 51, 0.5);
}

/* パーティクルの色バリエーション */
.particle.orange {
  background: radial-gradient(circle, rgba(255, 153, 51, 0.9) 0%, rgba(255, 200, 100, 0.6) 50%, transparent 100%);
  box-shadow: 0 0 6px rgba(255, 153, 51, 0.8), 0 0 12px rgba(255, 153, 51, 0.4);
}

.particle.red {
  background: radial-gradient(circle, rgba(255, 100, 50, 0.9) 0%, rgba(255, 150, 100, 0.6) 50%, transparent 100%);
  box-shadow: 0 0 6px rgba(255, 100, 50, 0.8), 0 0 12px rgba(255, 100, 50, 0.4);
}

.particle.yellow {
  background: radial-gradient(circle, rgba(255, 220, 100, 0.9) 0%, rgba(255, 240, 150, 0.6) 50%, transparent 100%);
  box-shadow: 0 0 6px rgba(255, 220, 100, 0.8), 0 0 12px rgba(255, 220, 100, 0.4);
}

.particle.purple {
  background: radial-gradient(circle, rgba(166, 51, 242, 0.7) 0%, rgba(200, 100, 255, 0.5) 50%, transparent 100%);
  box-shadow: 0 0 6px rgba(166, 51, 242, 0.6), 0 0 12px rgba(166, 51, 242, 0.3);
}

/* パーティクル上昇アニメーション */
@keyframes particle-rise {
  0% {
    transform: translateY(0) translateX(0) scale(1);
    opacity: 1;
  }
  50% {
    opacity: 0.8;
  }
  100% {
    transform: translateY(-100vh) translateX(var(--drift-x, 0)) scale(0.3);
    opacity: 0;
  }
}

.hero-content {
  text-align: center;
  position: relative;
  z-index: 1;
  max-width: 800px;
  padding: var(--spacing-md);
}

.hero-logo {
  margin-bottom: var(--spacing-md);
}

.flame-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--spacing-sm);
  object-fit: contain;
  animation: flicker 3s infinite;
}

.hero-title {
  font-size: 4rem;
  font-weight: 900;
  margin-bottom: var(--spacing-sm);
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.exclamation {
  color: var(--brand-orange);
  -webkit-text-fill-color: var(--brand-orange);
}

.hero-tagline {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

.hero-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

.hero-cta {
  margin-top: var(--spacing-lg);
  /* CTAを確実に前面にし、クリック/ホバーを受け取れるようにする */
  position: relative;
  z-index: 10;
  pointer-events: auto;
}

/* ============================================
   セクション共通スタイル
   ============================================ */
section {
  padding: var(--spacing-xl) 0;
  position: relative;
  transform-style: preserve-3d;
  transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 案4: セクション間トランジション */
section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, 
    transparent, 
    rgba(255, 153, 51, 0.5), 
    rgba(166, 51, 242, 0.5), 
    transparent
  );
  opacity: 0;
  transition: opacity 0.6s;
}

section.in-view::before {
  opacity: 1;
}

/* 案2: パララックス効果用のコンテナ */
.parallax-bg {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: 
    radial-gradient(circle at 20% 50%, rgba(255, 153, 51, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 50%, rgba(166, 51, 242, 0.1) 0%, transparent 50%);
  transform: translateZ(-1px) scale(2);
  z-index: -1;
  /* 重要: scale/translate でセクション外へはみ出してもクリック/ホバーを奪わない */
  pointer-events: none;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: var(--spacing-md);
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  /* 案4: ストロークアニメーション */
  position: relative;
  display: inline-block;
  opacity: 0;
  transform: translateY(-30px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.section-title.in-view {
  opacity: 1;
  transform: translateY(0);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--brand-orange), var(--brand-purple));
  transition: width 1s cubic-bezier(0.4, 0, 0.2, 1);
}

.section-title.in-view::after {
  width: 100%;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.125rem;
  margin-bottom: var(--spacing-lg);
}

/* ============================================
   特徴セクション
   ============================================ */
.features {
  background: var(--bg-surface);
  position: relative;
  /* parallax-bg(scale) のはみ出しを切り、ヒーロー等への被りを防ぐ */
  overflow: hidden;
}

/* 案2: 幾何学模様の背景 */
.features::before,
.decks::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    linear-gradient(30deg, rgba(255, 255, 255, 0.02) 12%, transparent 12.5%, transparent 87%, rgba(255, 255, 255, 0.02) 87.5%, rgba(255, 255, 255, 0.02)),
    linear-gradient(150deg, rgba(255, 255, 255, 0.02) 12%, transparent 12.5%, transparent 87%, rgba(255, 255, 255, 0.02) 87.5%, rgba(255, 255, 255, 0.02)),
    linear-gradient(30deg, rgba(255, 255, 255, 0.02) 12%, transparent 12.5%, transparent 87%, rgba(255, 255, 255, 0.02) 87.5%, rgba(255, 255, 255, 0.02)),
    linear-gradient(150deg, rgba(255, 255, 255, 0.02) 12%, transparent 12.5%, transparent 87%, rgba(255, 255, 255, 0.02) 87.5%, rgba(255, 255, 255, 0.02));
  background-size: 80px 140px;
  background-position: 0 0, 0 0, 40px 70px, 40px 70px;
  opacity: 0.3;
  z-index: 0;
  pointer-events: none;
}

.features > .container,
.decks > .container {
  position: relative;
  z-index: 1;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.feature-card {
  /* 案5: ネオモーフィズム効果 */
  background: var(--bg-surface);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  border: none;
  box-shadow: 
    -8px -8px 16px rgba(255, 255, 255, 0.05),
    8px 8px 16px rgba(0, 0, 0, 0.5),
    inset -4px -4px 8px rgba(255, 255, 255, 0.02),
    inset 4px 4px 8px rgba(0, 0, 0, 0.3);
  /* 案1: 3D効果 */
  transform-style: preserve-3d;
  position: relative;
  overflow: hidden;
  /* 案2: パララックス効果 + 案4: カードの順次表示アニメーション */
  opacity: 0;
  transform: translateY(50px) scale(0.9);
  transition: all 0.6s cubic-bezier(0.34, 1.56, 0.64, 1), transform 0.3s ease-out;
}

.feature-card:nth-child(1) { transition-delay: 0.1s; }
.feature-card:nth-child(2) { transition-delay: 0.2s; }
.feature-card:nth-child(3) { transition-delay: 0.3s; }
.feature-card:nth-child(4) { transition-delay: 0.4s; }
.feature-card:nth-child(5) { transition-delay: 0.5s; }
.feature-card:nth-child(6) { transition-delay: 0.6s; }

.feature-card.in-view {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.feature-card::before {
  /* 案1: カードの前面と背面 */
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(255, 153, 51, 0.1), rgba(166, 51, 242, 0.1));
  border-radius: var(--border-radius);
  opacity: 0;
  transition: opacity 0.4s;
  z-index: 0;
}

.feature-card > * {
  position: relative;
  z-index: 1;
}

.feature-card:hover {
  /* security-card と同等の演出 */
  transform: translateY(-4px);
  border-color: var(--brand-purple);
  box-shadow: var(--shadow-md);
}

.feature-card:hover::before {
  /* オーバーレイは非適用（security-cardに合わせる） */
  opacity: 0;
}

.feature-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
  display: inline-block;
  /* 案1: 3D回転の準備 */
  transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.feature-icon-img {
  width: 3rem;
  height: 3rem;
  min-width: 3rem;
  min-height: 3rem;
  margin-bottom: var(--spacing-sm);
  display: block;
  object-fit: contain;
  transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  flex-shrink: 0;
}

.feature-card:hover .feature-icon {
  /* 絵文字のホバー変化は非適用（security-cardに合わせる） */
  transform: none;
}

.feature-card:hover .feature-icon-img {
  transform: none;
}

.feature-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.feature-card:hover .feature-title {
  /* タイトルのホバー変化は非適用（security-cardに合わせる） */
  text-shadow: none;
}

.feature-description {
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================
   デッキセクション
   ============================================ */
.decks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

/* parallax-bg(scale) のはみ出しを切り、ヒーロー等への被りを防ぐ */
.decks {
  position: relative;
  overflow: hidden;
}

.deck-card {
  /* 案5: ネオモーフィズム効果 */
  background: var(--bg-surface);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  border: none;
  box-shadow: 
    -8px -8px 16px rgba(255, 255, 255, 0.05),
    8px 8px 16px rgba(0, 0, 0, 0.5),
    inset -4px -4px 8px rgba(255, 255, 255, 0.02),
    inset 4px 4px 8px rgba(0, 0, 0, 0.3);
  /* 案1: 3D効果 */
  transform-style: preserve-3d;
  position: relative;
  overflow: hidden;
  /* 案2: パララックス効果 + 案4: カードの順次表示アニメーション */
  opacity: 0;
  transform: translateY(50px) scale(0.9);
  transition: all 0.6s cubic-bezier(0.34, 1.56, 0.64, 1), transform 0.3s ease-out;
}

.deck-card:nth-child(1) { transition-delay: 0.1s; }
.deck-card:nth-child(2) { transition-delay: 0.2s; }
.deck-card:nth-child(3) { transition-delay: 0.3s; }
.deck-card:nth-child(4) { transition-delay: 0.4s; }
.deck-card:nth-child(5) { transition-delay: 0.5s; }

.deck-card.in-view {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.deck-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(51, 191, 217, 0.1), rgba(166, 51, 242, 0.1));
  border-radius: var(--border-radius);
  opacity: 0;
  transition: opacity 0.4s;
  z-index: 0;
}

.deck-card > * {
  position: relative;
  z-index: 1;
}

.deck-card:hover {
  /* security-card と同等の演出 */
  transform: translateY(-4px);
  border-color: var(--brand-purple);
  box-shadow: var(--shadow-md);
}

.deck-card:hover::before {
  /* オーバーレイは非適用（security-cardに合わせる） */
  opacity: 0;
}

.deck-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
  display: inline-block;
  /* 案1: 3D回転の準備 */
  transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.deck-card:hover .deck-icon {
  /* 絵文字のホバー変化は非適用（security-cardに合わせる） */
  transform: none;
}

.deck-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
  color: var(--text-primary);
}

.deck-card:hover .deck-title {
  /* タイトルのホバー変化は非適用（security-cardに合わせる） */
  text-shadow: none;
}

.deck-subtitle {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-sm);
  line-height: 1.6;
}

.deck-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
}

.deck-tags li {
  background: rgba(166, 51, 242, 0.2);
  color: var(--brand-purple);
  padding: 0.25rem 0.75rem;
  border-radius: 12px;
  font-size: 0.875rem;
  font-weight: 500;
}

/* ============================================
   学習モードセクション
   ============================================ */
.modes {
  background: var(--bg-surface);
  /* 案2: スクロール時の視差効果 */
  perspective: 1000px;
}

.modes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.mode-card {
  /* 案5: ネオモーフィズム効果 */
  background: var(--bg-surface);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  border: none;
  box-shadow: 
    -8px -8px 16px rgba(255, 255, 255, 0.05),
    8px 8px 16px rgba(0, 0, 0, 0.5),
    inset -4px -4px 8px rgba(255, 255, 255, 0.02),
    inset 4px 4px 8px rgba(0, 0, 0, 0.3);
  /* 案1: 3D効果 + 案2: スクロール時の視差効果 + 案4: カードの順次表示アニメーション */
  transform-style: preserve-3d;
  position: relative;
  overflow: hidden;
  opacity: 0;
  transform: translateY(50px) scale(0.9);
  transition: all 0.6s cubic-bezier(0.34, 1.56, 0.64, 1), transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
}

.mode-card:nth-child(1) { transition-delay: 0.1s; }
.mode-card:nth-child(2) { transition-delay: 0.2s; }
.mode-card:nth-child(3) { transition-delay: 0.3s; }
.mode-card:nth-child(4) { transition-delay: 0.4s; }

.mode-card.in-view {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.mode-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--brand-orange), var(--brand-purple));
  transform: scaleX(0);
  transition: transform 0.3s;
  z-index: 1;
}

.mode-card > * {
  position: relative;
  z-index: 1;
}

.mode-card:hover::before {
  transform: scaleX(1);
}

.mode-card:hover {
  /* security-card と同等の演出 */
  transform: translateY(-4px);
  border-color: var(--brand-purple);
  box-shadow: var(--shadow-md);
}

.mode-number {
  font-size: 3rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-sm);
}

.mode-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.mode-card:hover .mode-title {
  /* タイトルのホバー変化は非適用（security-cardに合わせる） */
  text-shadow: none;
}

.mode-description {
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================
   WordFire Proセクション
   ============================================ */
.pro {
  background: linear-gradient(135deg, rgba(255, 153, 51, 0.1), rgba(166, 51, 242, 0.1));
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.pro-content {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.pro-badge {
  display: inline-block;
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  color: var(--text-primary);
  padding: 0.5rem 1.5rem;
  border-radius: 20px;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  font-size: 0.875rem;
}

.pro-title {
  font-size: 3rem;
  font-weight: 900;
  margin-bottom: var(--spacing-sm);
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.pro-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

.pro-features {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  text-align: left;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

.pro-feature {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--text-primary);
  font-weight: 500;
  /* 案4: プログレスバー風のアニメーション */
  position: relative;
  overflow: hidden;
}

.pro-feature::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 0;
  background: linear-gradient(90deg, rgba(255, 153, 51, 0.2), rgba(166, 51, 242, 0.2));
  transition: width 1s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: -1;
}

.pro-feature.in-view::before {
  width: 100%;
}

.pro-feature svg {
  color: var(--brand-teal);
  flex-shrink: 0;
}

/* 案4: カウントアップアニメーション用 */
.counter {
  display: inline-block;
  font-variant-numeric: tabular-nums;
}

.pro-plans {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.plan-card {
  /* 案5: ネオモーフィズム効果 */
  background: var(--bg-surface);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  border: none;
  box-shadow: 
    -8px -8px 16px rgba(255, 255, 255, 0.05),
    8px 8px 16px rgba(0, 0, 0, 0.5),
    inset -4px -4px 8px rgba(255, 255, 255, 0.02),
    inset 4px 4px 8px rgba(0, 0, 0, 0.3);
  position: relative;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.plan-card:hover {
  box-shadow: 
    -12px -12px 24px rgba(255, 153, 51, 0.1),
    12px 12px 24px rgba(0, 0, 0, 0.6),
    inset -6px -6px 12px rgba(255, 255, 255, 0.03),
    inset 6px 6px 12px rgba(0, 0, 0, 0.4),
    0 0 40px rgba(255, 153, 51, 0.3);
  transform: translateY(-4px);
}

.plan-badge {
  position: absolute;
  top: -12px;
  right: var(--spacing-sm);
  background: var(--brand-teal);
  color: var(--bg-dark);
  padding: 0.25rem 0.75rem;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 700;
}

.plan-name {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.plan-price {
  font-size: 2rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-xs);
}

.plan-unit {
  font-size: 1rem;
  color: var(--text-secondary);
  -webkit-text-fill-color: var(--text-secondary);
}

.plan-subtitle {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* ============================================
   スクリーンショットセクション
   ============================================ */
.screenshots {
  background: var(--bg-surface);
}

.screenshots-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.screenshot-placeholder {
  aspect-ratio: 9 / 16;
  background: var(--bg-surface-light);
  border-radius: var(--border-radius);
  border: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.screenshot-placeholder img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center;
  display: block;
}

.screenshot-content {
  text-align: center;
  color: var(--text-secondary);
}

.screenshot-content p {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.screenshot-content small {
  color: var(--text-tertiary);
}

/* ============================================
   対応言語セクション
   ============================================ */
.languages {
  background: var(--bg-surface);
}

.languages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.language-card {
  background: var(--bg-surface-light);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  border: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  transition: all 0.3s;
}

.language-card:hover {
  transform: translateY(-4px);
  border-color: var(--brand-teal);
  box-shadow: var(--shadow-md);
}

.language-flag {
  font-size: 3rem;
  margin-bottom: var(--spacing-xs);
}

.language-name {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.languages-note {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-top: var(--spacing-md);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ============================================
   データ保存・セキュリティセクション
   ============================================ */
.security {
  background: var(--bg-dark);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.security-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.security-card {
  background: var(--bg-surface-light);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  border: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  transition: all 0.3s;
}

.security-card:hover {
  transform: translateY(-4px);
  border-color: var(--brand-purple);
  box-shadow: var(--shadow-md);
}

.security-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
}

.security-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.security-description {
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================
   FAQセクション
   ============================================ */
.faq {
  background: var(--bg-surface);
}

.faq-list {
  max-width: 800px;
  margin: var(--spacing-lg) auto 0;
}

.faq-item {
  background: var(--bg-surface-light);
  border-radius: var(--border-radius);
  border: 1px solid rgba(255, 255, 255, 0.1);
  margin-bottom: var(--spacing-sm);
  overflow: hidden;
  transition: all 0.3s;
}

.faq-item:hover {
  border-color: var(--brand-purple);
}

.faq-question {
  width: 100%;
  padding: var(--spacing-md);
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.125rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-sm);
  transition: color 0.3s;
}

.faq-question:hover {
  color: var(--brand-orange);
}

.faq-question[aria-expanded="true"] {
  color: var(--brand-orange);
}

.faq-icon {
  flex-shrink: 0;
  transition: transform 0.3s;
  color: var(--brand-purple);
}

.faq-question[aria-expanded="true"] .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out, padding 0.3s ease-out;
  padding: 0 var(--spacing-md);
}

.faq-item[aria-expanded="true"] .faq-answer {
  max-height: 500px;
  padding: 0 var(--spacing-md) var(--spacing-md);
}

.faq-answer p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin: 0;
}

.faq-answer a {
  color: var(--brand-orange);
  text-decoration: underline;
  transition: color 0.3s;
}

.faq-answer a:hover {
  color: var(--brand-purple);
}

/* ============================================
   フッター
   ============================================ */
.footer {
  background: var(--bg-surface);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: var(--spacing-lg) 0 var(--spacing-md);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.footer-title {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: var(--spacing-xs);
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.footer-tagline {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.footer-heading {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--spacing-xs);
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.3s;
}

.footer-links a:hover {
  color: var(--text-primary);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-md);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

/* ============================================
   エラーページ
   ============================================ */
.error-page {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 80px;
}

.error-content {
  text-align: center;
}

.error-content h1 {
  font-size: 6rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--brand-orange), var(--brand-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-md);
}

.error-content p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
}

/* ============================================
   アニメーション
   ============================================ */
@keyframes flicker {
  0%, 100% {
    opacity: 1;
    transform: rotate(0deg) scale(1);
  }
  25% {
    opacity: 0.9;
    transform: rotate(-4deg) scale(1.05);
  }
  50% {
    opacity: 1;
    transform: rotate(0deg) scale(1);
  }
  75% {
    opacity: 0.95;
    transform: rotate(4deg) scale(1.03);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 0.3;
    transform: scale(1);
  }
  50% {
    opacity: 0.5;
    transform: scale(1.1);
  }
}

/* ============================================
   レスポンシブデザイン
   ============================================ */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.5rem;
  }
  
  .hero-tagline {
    font-size: 1.25rem;
  }
  
  .section-title {
    font-size: 2rem;
  }
  
  .nav-links {
    flex-wrap: wrap;
    gap: var(--spacing-sm);
  }
  
  .features-grid,
  .decks-grid,
  .modes-grid {
    grid-template-columns: 1fr;
  }
  
  .pro-plans {
    grid-template-columns: 1fr;
  }
  
  .screenshots-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2rem;
  }
  
  .container {
    padding: 0 var(--spacing-sm);
  }
  
  .nav {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .nav-links {
    width: 100%;
    justify-content: center;
  }
}