/* 全体設定 */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  font-family: Arial, "Helvetica Neue", Helvetica, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f8f9fa;
}
a {
  color: #004085;
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* ヘッダー・フッター */
header {
  background-color: #ffffff;
  border-bottom: 3px solid #004085;
  padding: 15px 5%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}
header h1 {
  font-size: 1.2rem;
  color: #004085;
}
nav ul {
  display: flex;
  list-style: none;
  gap: 15px;
}
nav a {
  font-weight: bold;
  font-size: 0.9rem;
}
footer {
  background-color: #343a40;
  color: #ffffff;
  text-align: center;
  padding: 20px;
  margin-top: 40px;
  font-size: 0.85rem;
}

/* レイアウト・コンテナ */
.container {
  max-width: 1000px;
  margin: 30px auto;
  padding: 0 20px;
}
section {
  background: #ffffff;
  padding: 30px;
  margin-bottom: 20px;
  border-radius: 5px;
  border: 1px solid #dee2e6;
}

/* 見出し */
h2 {
  color: #004085;
  border-left: 5px solid #004085;
  padding-left: 10px;
  margin-bottom: 20px;
  font-size: 1.5rem;
}
h3 {
  color: #495057;
  margin: 20px 0 10px;
  font-size: 1.2rem;
}
h4 {
  color: #004085;
  margin: 15px 0 5px;
  font-size: 1.1rem;
}

/* リスト・テーブル・文字装飾 */
ul, ol {
  margin-left: 20px;
  margin-bottom: 15px;
}
li {
  margin-bottom: 5px;
}
table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
}
th, td {
  border: 1px solid #dee2e6;
  padding: 12px;
  text-align: left;
}
th {
  background-color: #e9ecef;
  color: #495057;
}
.accent-box {
  background-color: #e8f4fd;
  border-left: 5px solid #17a2b8;
  padding: 15px;
  margin: 15px 0;
  border-radius: 0 5px 5px 0;
}
.btn {
  display: inline-block;
  background-color: #004085;
  color: #fff;
  padding: 10px 20px;
  border-radius: 4px;
  font-weight: bold;
  margin-top: 10px;
}
.btn:hover {
  background-color: #002752;
  text-decoration: none;
  color: #fff;
}

/* トップページ用カードレイアウト */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  margin-top: 20px;
}
.card {
  background: #fff;
  border: 1px solid #dee2e6;
  padding: 20px;
  border-radius: 5px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

/* レスポンシブ（スマホ用） */
@media (max-width: 768px) {
  header { flex-direction: column; text-align: center; gap: 10px; }
  nav ul { flex-wrap: wrap; justify-content: center; }
}