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

:root {
  --bg-page: #11151f;
  --bg-card: #191f2e;
  --bg-card-sub: #141925;
  --bg-card-hover: #1f273a;
  --border-color: #283147;
  --border-sub: #334155;
  --text-main: #f8fafc;
  --text-body: #cbd5e1;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --primary: #3b5998;
  --primary-hover: #4a6cb3;
  --accent-link: #60a5fa;
  --accent-link-hover: #93c5fd;
  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.12);
  --success-border: rgba(52, 211, 153, 0.32);
  --success-text: #34d399;
  --warning-border: #f59e0b;
  --warning-bg: rgba(245, 158, 11, 0.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-full: 9999px;
  --max-width: 820px;
}

html {
  font-size: 15px;
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-page);
  color: var(--text-body);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* タイポグラフィガイドライン準拠 */
h1, h2, h3, h4 {
  color: var(--text-main);
  text-wrap: balance;
  line-height: 1.35;
  font-weight: 700;
}

p, li, blockquote {
  text-wrap: pretty;
  overflow-wrap: break-word;
}

a {
  color: var(--accent-link);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--accent-link-hover);
  text-decoration: underline;
}

/* ヘッダー・ナビゲーション */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(17, 21, 31, 0.88);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.85rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.site-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
}

.brand-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  object-fit: cover;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.brand-name {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.3px;
  color: var(--text-main);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-link {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
  text-decoration: none;
}

.nav-link:hover {
  color: var(--text-main);
  background-color: var(--bg-card);
  text-decoration: none;
}

.nav-link.active {
  color: #ffffff;
  background-color: var(--primary);
  text-decoration: none;
}

/* メインコンテナ */
.main-wrapper {
  flex: 1;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 2.25rem 1.25rem 4rem;
}

/* ヒーローセクション */
.hero-section {
  text-align: center;
  padding: 1.5rem 0 2.5rem;
}

.hero-badge-group {
  display: inline-flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 1.2rem;
}

.tag-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  background-color: var(--bg-card-sub);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
}

.tag-badge.accent {
  background-color: var(--success-bg);
  border-color: var(--success-border);
  color: var(--success-text);
}

.hero-title {
  font-size: clamp(1.75rem, 1.2rem + 2.4vw, 2.35rem);
  letter-spacing: -0.02em;
  margin-bottom: 0.85rem;
}

.hero-lead {
  font-size: clamp(1rem, 0.95rem + 0.4vw, 1.125rem);
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto 1.85rem;
}

.preview-container {
  display: flex;
  justify-content: center;
  margin: 1.5rem auto 0;
}

.preview-image {
  max-width: 330px;
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
}

/* カード共通スタイル */
.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.6rem;
  margin-bottom: 1.5rem;
}

.card-title-lg {
  font-size: 1.35rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.section-intro {
  color: var(--text-muted);
  margin-bottom: 1.4rem;
  font-size: 0.95rem;
}

/* ステップ手順コンポーネント */
.steps-grid {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
}

.step-card {
  background-color: var(--bg-card-sub);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.35rem;
  display: flex;
  gap: 1.1rem;
  align-items: flex-start;
}

.step-number {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background-color: var(--primary);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  margin-top: 0.15rem;
}

.step-content {
  flex: 1;
}

.step-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  color: var(--text-main);
}

.step-desc {
  font-size: 0.9rem;
  color: var(--text-body);
  margin-bottom: 0.75rem;
}

/* 公式リンクリスト */
.game-links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 0.75rem;
  margin-top: 0.65rem;
}

.game-link-box {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.75rem 0.9rem;
}

.game-link-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.45rem;
}

.game-action-links {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.8rem;
}

.game-action-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

/* 機能紹介グリッド */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1rem;
}

.feature-box {
  background-color: var(--bg-card-sub);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.1rem;
}

.feature-box-icon {
  font-size: 1.4rem;
  margin-bottom: 0.45rem;
  line-height: 1;
}

.feature-box-title {
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.35rem;
}

.feature-box-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* 注意書き・重要ボックス */
.notice-box {
  background-color: var(--bg-card-sub);
  border-left: 3px solid var(--warning-border);
  padding: 0.9rem 1.1rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.875rem;
  color: var(--text-body);
  margin: 1.15rem 0;
}

.notice-box strong {
  color: var(--text-main);
}

.notice-box.info {
  border-left-color: var(--accent-link);
}

/* よくある質問 (FAQ アコーディオン) */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.faq-item {
  background-color: var(--bg-card-sub);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color 0.15s ease;
}

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

.faq-question {
  padding: 0.95rem 1.15rem;
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
  gap: 0.5rem;
}

.faq-question::-webkit-details-marker {
  display: none;
}

.faq-question::after {
  content: "+";
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform 0.2s ease;
  line-height: 1;
}

.faq-item[open] .faq-question::after {
  content: "−";
  color: var(--accent-link);
}

.faq-answer {
  padding: 0 1.15rem 1.15rem;
  font-size: 0.875rem;
  color: var(--text-body);
  line-height: 1.6;
  border-top: 1px solid transparent;
}

.faq-item[open] .faq-answer {
  border-top-color: rgba(40, 49, 71, 0.6);
  padding-top: 0.8rem;
}

/* プライバシーポリシー用スタイル */
.policy-header {
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.25rem;
}

.policy-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.policy-section {
  margin-bottom: 2.25rem;
}

.policy-section h2 {
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-main);
}

.policy-section p {
  font-size: 0.925rem;
  margin-bottom: 0.85rem;
  color: var(--text-body);
}

.policy-section ul,
.policy-section ol {
  margin: 0.6rem 0 1rem 1.35rem;
  font-size: 0.9rem;
  color: var(--text-body);
}

.policy-section li {
  margin-bottom: 0.35rem;
}

/* テーブルスタイル */
.table-responsive {
  overflow-x: auto;
  margin: 1.15rem 0;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  text-align: left;
}

.data-table th,
.data-table td {
  padding: 0.75rem 0.95rem;
  border-bottom: 1px solid var(--border-color);
  vertical-align: top;
}

.data-table th {
  background-color: var(--bg-card-sub);
  color: var(--text-main);
  font-weight: 600;
  white-space: nowrap;
}

.data-table tr:last-child td {
  border-bottom: none;
}

.data-table td code {
  background-color: var(--bg-card-sub);
  padding: 0.15rem 0.35rem;
  border-radius: 4px;
  font-size: 0.8rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

/* フッター */
.site-footer {
  border-top: 1px solid var(--border-color);
  padding: 2.25rem 1.25rem;
  text-align: center;
  background-color: var(--bg-card-sub);
  margin-top: auto;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 0.9rem;
  font-size: 0.85rem;
}

.footer-nav a {
  color: var(--text-muted);
}

.footer-nav a:hover {
  color: var(--accent-link-hover);
}

.footer-disclaimer {
  font-size: 0.8rem;
  color: var(--text-dim);
  line-height: 1.5;
}

/* レスポンシブ調整 */
@media (max-width: 640px) {
  .header-inner {
    padding: 0.75rem 1rem;
  }

  .brand-name {
    font-size: 1.05rem;
  }

  .main-wrapper {
    padding: 1.5rem 1rem 3rem;
  }

  .step-card {
    flex-direction: column;
    gap: 0.65rem;
  }

  .step-number {
    width: 26px;
    height: 26px;
    font-size: 0.85rem;
  }

  .card {
    padding: 1.25rem;
  }

  .game-links-grid {
    grid-template-columns: 1fr;
  }
}