body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #f4f4f9;
}
.container {
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  max-width: 400px;
  width: 100%;
}
h1 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 24px;
  color: #333;
}
form {
  display: flex;
  flex-direction: column;
  gap: 15px;
}
.name-fields {
  display: flex;
  gap: 10px;
}
input {
  display: block;
  width: 100%;
  padding: 10px;
  font-size: 16px;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
}
button {
  padding: 10px;
  font-size: 16px;
  color: #fff;
  background-color: #007bff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s;
}
button:hover {
  background-color: #0056b3;
}
.error {
  color: red;
  font-size: 14px;
  text-align: center;
}

/* スナックバーのスタイル */
.snackbar {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background-color: #333;
  color: #fff;
  padding: 16px;
  border-radius: 4px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  font-size: 14px;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.snackbar.show {
  opacity: 1;
  visibility: visible;
}

.snackbar-success {
  background-color: #4caf50;
}

.snackbar-error {
  background-color: #f44336;
}

.snackbar-info {
  background-color: #2196f3;
}