:root {
    --primary: #4a6fa5;
    --secondary: #166088;
    --accent: #ff8c42;
    --background: #f5f7fa;
    --text: #333;
    --success: #52b788;
    --danger: #e63946;
  }
  
  body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background);
    color: var(--text);
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
  }
  
  .container {
    width: 90%;
    max-width: 800px;
    margin: 2rem auto;
    text-align: center;
  }
  
  h1 {
    color: var(--primary);
    margin-bottom: 1rem;
  }
  
  .game-info {
    display: flex;
    justify-content: space-around;
    margin-bottom: 1.5rem;
    background: white;
    padding: 1rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  }
  
  .info-item {
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  
  .info-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--secondary);
  }
  
  .timer-container {
    width: 100%;
    background-color: #e9ecef;
    height: 10px;
    border-radius: 5px;
    margin: 1rem 0;
    overflow: hidden;
  }
  
  .timer-bar {
    height: 100%;
    background-color: var(--accent);
    width: 100%;
    border-radius: 5px;
    transition: width 0.1s linear;
  }
  
  .hearts {
    display: flex;
    justify-content: center;
    margin-bottom: 1rem;
  }
  
  .heart {
    color: var(--danger);
    font-size: 2rem;
    margin: 0 0.5rem;
  }
  
  .game-buttons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
  }
  
  .number-btn {
    background-color: white;
    border: 2px solid var(--primary);
    color: var(--primary);
    font-size: 1.25rem;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 100px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  }
  
  .number-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
  }
  
  .number-btn.correct {
    background-color: var(--success);
    color: white;
    border-color: var(--success);
  }
  
  .number-btn.incorrect {
    background-color: var(--danger);
    color: white;
    border-color: var(--danger);
  }
  
  .order-instruction {
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--secondary);
    margin-bottom: 1rem;
    background: white;
    padding: 0.75rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    display: inline-block;
  }
  
  .start-screen, .end-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10;
  }
  
  .start-content, .end-content {
    background-color: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
    max-width: 500px;
    width: 90%;
    text-align: center;
  }
  
  .mode-selection {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin: 1.5rem 0;
  }
  
  .mode-btn, .start-btn, .restart-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s;
  }
  
  .mode-btn:hover, .start-btn:hover, .restart-btn:hover {
    background-color: var(--secondary);
  }
  
  .mode-btn.selected {
    background-color: var(--accent);
  }
  
  .result-item {
    margin: 1rem 0;
    font-size: 1.2rem;
  }
  
  .result-value {
    font-weight: bold;
    color: var(--accent);
    font-size: 1.5rem;
  }
  
  .settings-group {
    margin: 1.5rem 0;
    padding: 1rem;
    background-color: #f8f9fa;
    border-radius: 8px;
  }
  
  .settings-title {
    color: var(--secondary);
    margin-bottom: 0.5rem;
  }
  
  .setting-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 0.5rem 0;
  }
  
  .setting-label {
    margin-right: 1rem;
  }
  
  .setting-input {
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    width: 100px;
    text-align: center;
  }
  
  .debug-info {
    position: fixed;
    bottom: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    padding: 10px;
    border-radius: 5px;
    font-size: 0.8rem;
    z-index: 100;
    display: none;
  }
  
  @keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
  }
  
  .pulse {
    animation: pulse 0.5s;
  }