body {
    background-color: #1a1a1a;
    color: #f0f0f0;
    font-family: 'Helvetica Neue', 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

#quiz-container {
    width: 90%;
    max-width: 600px;
    padding: 20px;
    background-color: #2c2c2c;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
    text-align: center;
}

#question-area {
    margin-bottom: 30px;
}

#author {
    font-size: 1.2rem;
    color: #a0a0a0;
    margin: 0 0 20px;
}

.brush-font {
    font-family: 'Yuji Syuku', serif;
    font-size: 2rem;
    line-height: 1.6;
}

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

.option {
    padding: 15px;
    background-color: #444;
    border: 2px solid #555;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s, border-color 0.3s;
}

.option:hover {
    background-color: #555;
    border-color: #777;
}

.option.correct {
    background-color: #28a745; /* Green */
    color: #fff;
    border-color: #28a745;
}

.option.incorrect-answer {
    background-color: #dc3545; /* Red */
    color: #fff;
    border-color: #dc3545;
}

/* ユーザーが選択した不正解の選択肢 */
.option.selected-wrong {
    background-color: #6c757d; /* Gray */
    opacity: 0.7;
}

#feedback-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: transparent;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    pointer-events: none; /* Clicks pass through */
}

#feedback-overlay.hidden {
    display: none;
}

#feedback-text {
    font-size: 15rem;
    font-weight: bold;
    color: white;
    user-select: none;
    text-shadow: 0 0 15px rgba(0, 0, 0, 0.7);
}

#feedback-text.correct {
    color: rgba(40, 167, 69, 0.8); /* Green */
}

#feedback-text.incorrect {
    color: rgba(220, 53, 69, 0.8); /* Red */
}


#controls-area {
    margin-top: 30px;
    position: relative;
    z-index: 1001;
}

#next-button {
    padding: 12px 25px;
    font-size: 1rem;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s;
}

#next-button:hover {
    background-color: #0056b3;
}

#next-button.hidden {
    display: none;
}

/* スマートフォン向けのスタイル */
@media (max-width: 600px) {
    #quiz-container {
        width: 100%;
        min-height: 100vh;
        border-radius: 0;
        padding: 15px;
        box-sizing: border-box;
    }

    .brush-font {
        font-size: 1.2rem;
    }

    .option {
        padding: 12px;
        font-size: 1.2rem;
    }

    #feedback-text {
        font-size: 10rem;
    }
}