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

body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 600px;
}

.quiz-box {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #2d3748;
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
}

.score-container {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1.5rem;
    color: #4a5568;
    font-size: 1.1rem;
}

.question-container {
    background: #f7fafc;
    padding: 1.5rem;
    border-radius: 12px;
    margin-bottom: 1.5rem;
}

#question {
    font-size: 1.2rem;
    color: #2d3748;
    text-align: center;
    line-height: 1.6;
}

.buttons-container {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.answer-btn {
    padding: 1rem 2rem;
    font-size: 1.2rem;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: transform 0.2s, background-color 0.2s;
    width: 120px;
}

#true-btn {
    background-color: #48bb78;
    color: white;
}

#false-btn {
    background-color: #f56565;
    color: white;
}

.answer-btn:hover {
    transform: translateY(-2px);
    opacity: 0.9;
}

.next-btn {
    display: block;
    width: 100%;
    padding: 1rem;
    background-color: #4299e1;
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: background-color 0.2s;
}

.next-btn:hover {
    background-color: #3182ce;
}

.result {
    text-align: center;
    margin: 1rem 0;
    padding: 1rem;
    border-radius: 10px;
    font-size: 1.1rem;
}

.correct {
    background-color: #c6f6d5;
    color: #2f855a;
}

.incorrect {
    background-color: #fed7d7;
    color: #c53030;
}

.hidden {
    display: none;
}

.loading {
    text-align: center;
    padding: 2rem;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid #f3f3f3;
    border-top: 5px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 반응형 디자인 */
@media (max-width: 480px) {
    .quiz-box {
        padding: 1rem;
    }

    h1 {
        font-size: 1.5rem;
    }

    .buttons-container {
        flex-direction: column;
    }

    .answer-btn {
        width: 100%;
    }
}