:root {
  --color-bg: #ffffff;
  --color-bg-secondary: #f5f5f5;
  --color-text: #333333;
  --color-text-secondary: #666666;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-border: #e0e0e0;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  --radius: 8px;
  --transition: 0.2s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1a1a1a;
    --color-bg-secondary: #2d2d2d;
    --color-text: #e0e0e0;
    --color-text-secondary: #a0a0a0;
    --color-primary: #3b82f6;
    --color-primary-hover: #60a5fa;
    --color-border: #404040;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  }
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
}
a { color: var(--color-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-primary-hover); }
.container { max-width: 960px; margin: 0 auto; padding: 0 1rem; }

/* ヘッダー */
.header {
  background-color: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
}
.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem;
  max-width: 960px;
  margin: 0 auto;
}
.header__logo { font-weight: bold; font-size: 1.1rem; color: var(--color-text); }
.header__nav a { margin-left: 1.25rem; font-size: 0.9rem; }

/* ヒーロー（トップ） */
.hero { padding: 4rem 0 2rem; text-align: center; }
.hero__title { font-size: 2.25rem; font-weight: bold; margin-bottom: 0.5rem; }
.hero__lead { color: var(--color-text-secondary); }

.main { padding: 1.5rem 0 3rem; }

/* カード（トップのリンク） */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}
.card {
  display: block;
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: box-shadow var(--transition), transform var(--transition);
}
.card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.card__title { font-size: 1.25rem; margin-bottom: 0.5rem; color: var(--color-text); }
.card__description { color: var(--color-text-secondary); font-size: 0.9rem; }

/* 文書ページ（プライバシーポリシー等） */
.doc-content { max-width: 800px; margin: 0 auto; }
.doc-content h1 { font-size: 1.75rem; margin-bottom: 0.5rem; }
.doc-content h2 {
  margin-top: 2rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
  font-size: 1.25rem;
}
.doc-content p { margin-bottom: 1rem; line-height: 1.8; }
.doc-content ul { margin-bottom: 1rem; padding-left: 1.5rem; }
.doc-content li { margin-bottom: 0.5rem; line-height: 1.8; }
.doc-date { color: var(--color-text-secondary); font-size: 0.875rem; margin-bottom: 2rem; }

.info-table { width: 100%; border-collapse: collapse; margin-bottom: 1.5rem; }
.info-table th, .info-table td {
  padding: 0.75rem 1rem;
  border: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
}
.info-table th { background-color: var(--color-bg-secondary); white-space: nowrap; }

.footer {
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 0;
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  text-align: center;
}