body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #f4f4f9;
    color: #333;
    display: flex;
    justify-content: center;
    padding: 2rem;
}

.container {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    max-width: 600px;
    width: 100%;
}

.hidden {
    display: none !important;
}

button {
    background-color: #0056b3;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    margin-top: 10px;
}

button:hover:not(:disabled) {
    background-color: #004494;
}

.option-btn {
    display: block;
    width: 100%;
    text-align: left;
    background-color: #e9ecef;
    color: #333;
    margin-bottom: 10px;
}

.option-btn:disabled {
    cursor: not-allowed;
    opacity: 0.8;
}

.correct {
    background-color: #28a745 !important;
    color: white !important;
}

.wrong {
    background-color: #dc3545 !important;
    color: white !important;
}

#feedback {
    margin-top: 15px;
    padding: 15px;
    background-color: #f8f9fa;
    border-left: 4px solid #0056b3;
}