body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 20px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: #f4f4f9;
  text-align: center;
}

.container {
  display: flex;
  flex-direction: column;
  gap: 15px;
  width: 90%;
  max-width: 800px;
  margin: 0 auto; /* 横中央に揃える */
}

h1 {
  font-size: 1.8rem;
  margin: 0;
  color: #333;
}

p {
  font-size: 0.95rem;
  margin: 0 0 10px;
  color: #555;
}

textarea {
  width: 100%;
  height: 250px;
  padding: 10px;
  font-size: 14px;
  resize: vertical;
  border: 1px solid #ccc;
  border-radius: 8px;
  background: white;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.buttons {
  display: flex;
  justify-content: center;
  gap: 15px;
}

button {
  padding: 10px 15px;
  font-size: 14px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  background: #007bff;
  color: white;
  transition: 0.3s;
}

button:disabled {
  background: #999;
  cursor: not-allowed;
}

button:hover:enabled {
  background: #0056b3;
}

footer {
  margin-top: 30px;
  padding: 20px 0;
  color: #fff;
  text-align: center;
}

.footer-links {
  margin-bottom: 10px;
}

.footer-links a {
  margin: 0 10px;
  color: #fff;
  font-size: 1.4rem;
  transition: 0.3s;
}

footer p {
  font-size: 0.85rem;
  color: #ccc;
  margin: 0;
}

@media (max-width: 768px) {
  textarea {
    height: 200px;
  }

  .buttons {
    flex-direction: column;
    gap: 10px;
  }
}