body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: #f4f7f6;
  color: #333;
  margin: 0;
  padding: 20px;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 20px;
  background-color: #fff;
  border-bottom: 1px solid #ddd;
  margin-bottom: 20px;
}

header h1 {
  margin: 0;
  font-size: 1.5em;
}

header nav {
    display: flex;
    align-items: center;
    gap: 1rem;
}

#auth-container, #history-list-container {
  max-width: 800px;
  margin: 40px auto;
  padding: 20px;
  background-color: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  text-align: center;
}

button {
  background-color: #007bff;
  color: white;
  border: none;
  padding: 10px 15px;
  border-radius: 5px;
  cursor: pointer;
  font-size: 1em;
}

button:hover {
  background-color: #0056b3;
}

#logout-button {
    background-color: #dc3545;
}

#logout-button:hover {
    background-color: #c82333;
}

/* 履歴リストのスタイル */
.history-list {
  list-style: none;
  padding: 0;
  text-align: left;
}

.history-item a {
  display: block;
  padding: 15px;
  border-bottom: 1px solid #eee;
  text-decoration: none;
  color: #333;
  transition: background-color 0.2s;
}

.history-item a:hover {
  background-color: #f9f9f9;
}

.history-date {
  font-weight: bold;
  margin-right: 15px;
}

.history-mode {
  display: inline-block;
  margin-right: 15px;
  padding: 3px 8px;
  background-color: #e9ecef;
  border-radius: 4px;
  font-size: 0.9em;
}

.history-score {
  font-style: italic;
}

.auth-note {
  margin-top: 20px;
  font-size: 0.9em;
  color: #666;
}