body {
  font-family: 'Helvetica Neue', sans-serif;
  line-height: 1.7;
  padding: 2em;
  max-width: 800px;
  margin: auto;
  background: #f9f9f9;
  color: #333;
}

h1 {
  font-size: 1.8em;
  border-bottom: 2px solid #666;
  padding-bottom: 0.4em;
  margin-bottom: 1em;
}

h2 {
  font-size: 1.4em;
  margin-top: 2em;
  border-left: 4px solid #666;
  padding-left: 0.5em;
}

p, li {
  margin: 0.8em 0;
}

ul {
  padding-left: 1.2em;
}

footer {
  margin-top: 3em;
  padding-top: 2em;
  border-top: 1px solid #ddd;
}

/* 閉じるボタンのスタイル */
.close-button-container {
  text-align: right;
  margin-bottom: 1em;
}

.close-button {
  background: #666;
  color: white;
  border: none;
  padding: 0.5em 1em;
  border-radius: 4px;
  cursor: pointer;
}

.close-button:hover {
  background: #555;
}