/* 全体 */
body {
  font-family: "Yu Gothic", sans-serif;
  margin: 0;
  padding: 0;
  background: #f3f6ff;
  color: #333;
  line-height: 1.8;
}

/* ヘッダー */
header {
  background: linear-gradient(135deg, #1f3c88, #2a4d9b);
  color: white;
  padding: 30px 20px;
  text-align: center;
  box-shadow: 0 3px 10px rgba(0,0,0,0.2);
}

header h1 {
  margin: 0;
  font-size: 2.2rem;
  letter-spacing: 1px;
}

/* ナビバー */
nav {
  background: #1f3570;
  padding: 12px;
  text-align: center;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav a {
  color: white;
  margin: 0 18px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1.05rem;
}

nav a:hover {
  text-decoration: underline;
}

/* ヒーローセクション */
.hero {
  background: url('https://images.unsplash.com/photo-1529070538774-1843cb3265df?auto=format&fit=crop&w=1200&q=60') center/cover;
  padding: 80px 20px;
  color: white;
  text-align: center;
}

.hero h2 {
  font-size: 2.4rem;
  margin-bottom: 10px;
  text-shadow: 0 2px 6px rgba(0,0,0,0.4);
}

.hero p {
  font-size: 1.2rem;
  text-shadow: 0 2px 6px rgba(0,0,0,0.4);
}

/* メイン */
main {
  max-width: 1100px;
  margin: 40px auto;
  padding: 0 20px;
}

/* カードレイアウト */
.card-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 25px;
}

.card {
  background: white;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  transition: 0.2s;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 16px rgba(0,0,0,0.15);
}

.card h3 {
  margin-top: 0;
  color: #2a4d9b;
}

/* フッター */
footer {
  text-align: center;
  padding: 25px;
  background: #2a4d9b;
  color: white;
  margin-top: 50px;
}