body {
  font-family: "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  min-height: 100vh;
  margin: 0;
  background-color: #f0f6ff;
  padding: 20px;
}

/* フォーム全体 */
form {
  background-color: #ffffff;
  padding: 20px;
  margin: 15px 0;
  border-radius: 12px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  width: 100%;
  max-width: 500px;
}

/* ラベルと入力欄 */
label {
  font-weight: bold;
  color: #333;
}

input[type="text"] {
  width: 100%;
  padding: 10px;
  margin-top: 6px;
  margin-bottom: 12px;
  border: 1px solid #bbb;
  border-radius: 6px;
  box-sizing: border-box;
}

/* ボタン */
input[type="submit"] {
  background-color: #007BFF;
  color: white;
  padding: 12px 18px;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  width: 100%;
  font-size: 16px;
  transition: background 0.3s;
}

input[type="submit"]:hover {
  background-color: #0056b3;
}

/* テーブル */
table {
  width: 100%;
  max-width: 800px;
  border-collapse: collapse;
  margin-top: 20px;
  background-color: #fff;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

th, td {
  border: 1px solid #ddd;
  padding: 12px 15px;
  text-align: left;
}

th {
  background-color: #007BFF;
  color: white;
}

tr:nth-child(even) {
  background-color: #f9f9f9;
}

/* 戻るリンク */
a {
  display: inline-block;
  margin-top: 20px;
  text-decoration: none;
  color: #007BFF;
  font-weight: bold;
}

a:hover {
  text-decoration: underline;
}

/* モーダル背景（半透明） */
.modal-bg {
  display: none; /* 初期は非表示 */
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0, 0, 0, 0.4);
  z-index: 1000;
}

/* モーダル本体 */
.modal-content {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  background: white;
  padding: 20px;
  border-radius: 10px;
  min-width: 250px;
  text-align: center;
  box-shadow: 0 0 10px rgba(0,0,0,0.3);
}