body {
  margin: 0;
  background-color: #e6f2e6;
  color: #333333;
  font-family: Tahoma, Verdana, Arial, sans-serif;
  line-height: 1.5;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
}

.container {
  max-width: 1000px;
  text-align: center;
  background-color: #ffffff;
  margin: 50px 20px;
  padding: 2rem 4rem;
  border-radius: 8px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

h1 {
  font-size: 2.5rem;
  text-align: center;
  color: #2d6a4f;
}

/* 画面幅が小さい場合の調整 */
@media (max-width: 768px) {
  h1 {
    font-size: 2em;
  }
  .container {
    padding: 1rem 2rem;
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.5rem;
  }
  .container {
    padding: 1rem 2rem;
  }
}