body {
    font-family: 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
    background-color: #121212;
    color: #ffffff;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    text-align: center;
}

#container {
    width: 90%;
    max-width: 500px;
    padding: 20px;
    background-color: #1e1e1e;
    border-radius: 15px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

h1 {
    margin-top: 0;
}

button {
    background-color: #007bff;
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.2em;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    margin-top: 20px;
}

button:hover {
    background-color: #0056b3;
    transform: scale(1.05);
}

button:disabled {
    background-color: #555;
    cursor: not-allowed;
}

.hide {
    display: none;
}

#quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    font-size: 1.2em;
}

#timer {
    width: 40px;
    height: 40px;
    background-color: #007bff;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
}

#flag-container {
    margin-bottom: 20px;
    height: 180px;
    display: flex;
    justify-content: center;
    align-items: center;
}

#flag-img {
    max-width: 100%;
    max-height: 100%;
    height: auto;
    border: 2px solid #444;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

#options-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.option {
    width: 100%;
    padding: 15px 5px;
    font-size: 1em;
    margin: 0;
    background-color: #333;
}

.option:hover:not(:disabled) {
    background-color: #444;
}

.option.correct {
    background-color: #28a745;
}

.option.incorrect {
    background-color: #dc3545;
}

#result-screen h1 {
    margin-bottom: 20px;
}

#result-screen p {
    font-size: 1.5em;
    margin: 15px 0;
}

#result-message {
    font-size: 1.2em;
    font-weight: bold;
    min-height: 30px;
}

@media (max-width: 600px) {
    #container {
        width: 95%;
        padding: 15px;
    }

    button {
        padding: 12px 24px;
        font-size: 1em;
    }

    #options-container {
        grid-template-columns: 1fr;
        gap: 10px;
    }

    .option {
        padding: 12px 5px;
    }

    #flag-container {
        height: 150px;
    }
}