body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.7;
    background-color: #f8f9fa;
    color: #343a40;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 960px;
    margin: 20px auto;
    padding: 0 15px;
}

header {
    background-color: #004a99;
    color: white;
    padding: 25px 0;
    text-align: center;
    border-radius: 8px 8px 0 0;
}

header h1 {
    margin: 0;
    font-size: 2.5rem;
}

nav {
    display: flex;
    justify-content: center;
    background-color: #343a40;
    padding: 10px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav a {
    color: white;
    text-decoration: none;
    padding: 10px 20px;
    font-weight: bold;
    transition: background-color 0.3s;
}

nav a:hover {
    background-color: #0056b3;
}

article {
    background-color: #ffffff;
    padding: 30px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    scroll-margin-top: 70px;
}

article h2 {
    font-size: 2rem;
    color: #004a99;
    border-bottom: 3px solid #e9ecef;
    padding-bottom: 10px;
    margin-top: 0;
}

article h3 {
    font-size: 1.5rem;
    color: #17a2b8;
    margin-top: 25px;
    margin-bottom: 10px;
}

article h4 {
    font-size: 1.2rem;
    color: #343a40;
    font-style: italic;
    margin-top: 20px;
}

ul {
    padding-left: 25px;
    list-style-type: disc;
}

li {
    margin-bottom: 12px;
}

ul ul {
    list-style-type: circle;
    margin-top: 10px;
}

footer {
    text-align: center;
    padding-top: 30px;
    padding-bottom: 40px;
    margin-top: 20px;
    background-color: #343a40;
    color: #f8f9fa;
    border-radius: 0 0 8px 8px;
}

.footer-title {
    color: #ffffff;
    font-size: 1.5rem;
    margin-top: 25px;
    margin-bottom: 25px;
    font-weight: 500;
}

.member-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px 30px;
    max-width: 960px;
    margin: 0 auto;
}

.member-item {
    color: #f8f9fa;
    font-size: 1rem;
    background-color: #495057;
    padding: 8px 15px;
    border-radius: 4px;
    white-space: nowrap;
}

.mindmap-container {
    background-color: #fff;
    padding: 30px;
    margin: 20px auto;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    text-align: center;
    max-width: 960px;
}

.mindmap-container h2 {
    color: #004a99;
    margin-top: 0;
    margin-bottom: 25px;
}

.button-row {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.mindmap-button {
    display: inline-block;
    background-color: #28a745;
    color: white;
    padding: 12px 24px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    font-size: 1rem;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    font-family: inherit;
}

.mindmap-button:hover {
    background-color: #218838;
    transform: translateY(-2px);
}

.instruction {
    margin-top: 25px;
    color: #555;
    font-size: 0.9rem;
    font-style: italic;
}

.quiz-answer-paragraph {
    margin-top: 10px;
    margin-bottom: 10px;
    padding-left: 20px;
}

.quiz-answer-list {
    list-style-type: decimal;
    padding-left: 40px;
    margin-top: 15px;
}

.quiz-answer-list li {
    margin-bottom: 10px;
}

.quiz-answer-sublist {
    list-style-type: disc;
    padding-left: 40px;
    margin-top: 10px;
}

.quiz-answer-sublist li {
    margin-bottom: 8px;
}

.quiz-list {
    list-style-type: none;
    padding-left: 0;
}

.quiz-item {
    padding-bottom: 20px;
    margin-bottom: 20px;
    border-bottom: 1px solid #e0e0e0;
}

.quiz-item p {
    font-size: 1.1rem;
    margin-bottom: 10px;
}

.quiz-options {
    margin-top: 10px;
    margin-bottom: 15px;
}

.quiz-options label {
    margin-right: 25px;
    font-size: 1.05rem;
    cursor: pointer;
}

.quiz-options input[type="radio"] {
    margin-right: 5px;
    cursor: pointer;
}

.quiz-answer {
    display: none;
    padding: 12px 18px;
    margin-top: 15px;
    border-radius: 5px;
    font-weight: 500;
    line-height: 1.6;
    border-left-width: 5px;
    border-left-style: solid;
}

.quiz-answer.show {
    display: block;
}

.quiz-answer.correct {
    background-color: #d4edda;
    color: #155724;
    border-color: #155724;
}

.quiz-answer.incorrect {
    background-color: #f8d7da;
    color: #721c24;
    border-color: #721c24;
}

.quiz-link-paragraph {
    font-size: 1.1rem;
    font-weight: 500;
    margin-top: 15px;
    padding-left: 20px;
}

.quiz-link {
    color: #28a745;
    font-weight: bold;
    text-decoration: underline;
    cursor: pointer;
}

.quiz-link:hover {
    color: #218838;
}

.quiz-options.vertical label {
    display: block;
    margin-bottom: 10px;
    padding: 8px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.quiz-options.vertical label:hover {
    background-color: #f4f4f4;
}

.quiz-options.vertical label:last-child {
    margin-bottom: 0;
}