body {
    background-color: #e9ecef;
    font-family: 'Pretendard', sans-serif;
}

.container {
    max-width: 800px;
}

.card {
    background-color: white;
    border: none;
    border-radius: 15px;
    transition: all 0.3s ease-in-out;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.12) !important;
}

.btn-primary {
    background-color: #007bff;
    border-color: #007bff;
    transition: background-color 0.2s, border-color 0.2s;
}

.btn-primary:hover {
    background-color: #0056b3;
    border-color: #0056b3;
}

.btn-outline-primary {
    border-color: #007bff;
    color: #007bff;
    transition: background-color 0.2s, color 0.2s;
}

.btn-outline-primary:hover {
    background-color: #007bff;
    color: white;
}

.progress-bar {
    transition: width 0.5s ease-in-out;
}

#quiz-screen, #result-screen, #start-screen {
    animation: fadeIn 0.8s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Mobile Optimization */
@media (max-width: 768px) {
    .card {
        padding: 2rem !important;
    }
    h1 {
        font-size: 1.75rem;
    }
    .lead {
        font-size: 1rem;
    }
    .btn-lg {
        font-size: 1rem;
        padding: 0.7rem 1.2rem;
    }
    #question-title {
        font-size: 1.25rem;
    }
}