* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #2c3e50;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    text-align: center;
    margin-bottom: 40px;
    padding: 40px 0;
}

.title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 15px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.subtitle {
    font-size: 1.1rem;
    color: #7f8c8d;
    font-weight: 300;
}

.quiz-container {
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
    flex: 1;
}

.progress-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 30px;
}

.progress-bar {
    flex: 1;
    height: 8px;
    background: #ecf0f1;
    border-radius: 4px;
    overflow: hidden;
    margin-right: 20px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 6.67%;
}

.progress-text {
    font-size: 0.9rem;
    color: #7f8c8d;
    font-weight: 500;
    min-width: 60px;
}

.question-container {
    margin-bottom: 40px;
}

.question-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 25px;
    line-height: 1.5;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option {
    background: #f8f9fa;
    border: 2px solid #e9ecef;
    border-radius: 12px;
    padding: 18px 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
    line-height: 1.4;
}

.option:hover {
    background: #e3f2fd;
    border-color: #2196f3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.15);
}

.option.selected {
    background: #e8f5e8;
    border-color: #4caf50;
    color: #2e7d32;
    font-weight: 500;
}

.option-label {
    font-weight: 600;
    margin-right: 8px;
    color: #3498db;
}

.navigation-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

.nav-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 100px;
}

.prev-btn {
    background: #ecf0f1;
    color: #7f8c8d;
}

.prev-btn:not(:disabled):hover {
    background: #bdc3c7;
    color: #2c3e50;
}

.prev-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.next-btn, .submit-btn {
    background: linear-gradient(135deg, #3498db, #2ecc71);
    color: white;
}

.next-btn:not(:disabled):hover, .submit-btn:hover {
    background: linear-gradient(135deg, #2980b9, #27ae60);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

.next-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.result-container {
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
    text-align: center;
}

.result-card {
    max-width: 600px;
    margin: 0 auto;
}

.result-title {
    font-size: 2rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 30px;
}

.score-display {
    margin-bottom: 30px;
    padding: 20px;
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    border-radius: 12px;
}

.score-label {
    font-size: 1.2rem;
    color: #7f8c8d;
}

.score-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: #3498db;
    margin: 0 10px;
}

.score-total {
    font-size: 1.2rem;
    color: #7f8c8d;
}

.result-text {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #2c3e50;
    margin-bottom: 30px;
    text-align: left;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 12px;
    border-left: 4px solid #3498db;
}

.restart-btn {
    background: linear-gradient(135deg, #e74c3c, #c0392b);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 12px 30px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.restart-btn:hover {
    background: linear-gradient(135deg, #c0392b, #a93226);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(231, 76, 60, 0.3);
}

.footer {
    text-align: center;
    padding: 20px 0;
    color: #7f8c8d;
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .title {
        font-size: 2rem;
    }
    
    .quiz-container {
        padding: 25px;
    }
    
    .question-title {
        font-size: 1.2rem;
    }
    
    .option {
        padding: 15px;
        font-size: 0.95rem;
    }
    
    .navigation-container {
        flex-direction: column;
        gap: 15px;
    }
    
    .nav-btn {
        width: 100%;
        min-width: auto;
    }
    
    .result-container {
        padding: 25px;
    }
    
    .result-title {
        font-size: 1.6rem;
    }
    
    .score-value {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .title {
        font-size: 1.8rem;
    }
    
    .quiz-container {
        padding: 20px;
    }
    
    .question-title {
        font-size: 1.1rem;
    }
    
    .option {
        padding: 12px;
        font-size: 0.9rem;
    }
}