body {
  font-family: sans-serif;
  line-height: 1.7;

  max-width: 1100px;
  margin: 40px auto;
  padding: 0 20px;

  color: #222;
}

/* タイトル */
h1 {
  text-align: center;
  margin-bottom: 30px;
}

/* 見出し */
h1, h2, h3 {
  color: #1f3c88;
}

h2 {
  border-bottom: 2px solid #999;
  padding-bottom: 5px;
  margin-top: 40px;
}

/* メニューを中央に */
ul {
  display: flex;
  justify-content: center;
  gap: 20px;

  list-style: none;
  padding: 0;
  margin-bottom: 30px;
}

/* テーブル */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 15px;
  table-layout: fixed;  /* ←重要 */
}

/* 列ごとの幅 */
th:nth-child(1), td:nth-child(1) {
  width: 8%;
  text-align: center;
}

th:nth-child(2), td:nth-child(2) {
  width: 15%;
}

th:nth-child(3), td:nth-child(3) {
  width: 62%;
}

th:nth-child(4), td:nth-child(4) {
  width: 15%;
  text-align: center;
}

/* セル */
th, td {
  border: 1px solid #999;
  padding: 10px;
  text-align: left;
  word-wrap: break-word;  /* 長文対応 */
}

th {
  background: #f0f4ff;
}

/* 行 */
tr {
  height: 40px;
}

/* リンク */
a {
  color: #0055aa;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* 段落 */
p {
  text-indent: 1em;
}

.back-to-top {
  position: fixed;
  bottom: 50px;
  right: 50px;

  font-size: 16px;
  color: #0055aa;

  text-decoration: none;
  opacity: 0.7;
}

.back-to-top:hover {
  opacity: 1;
}

footer {
  margin-top: 50px;
  text-align: center;
  font-size: 13px;
  opacity: 0.8;
}

footer p {
  margin: 5px 0;
}