.back-link {
    display: inline-flex;
    align-items: center;
    padding: 0.5rem 1rem;
    margin: 0.5rem 0.5rem 0;
    color: #475569;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: 6px;
    background-color: #f8fafc;
    border: 1px solid #e2e8f0;
    transition: all 0.2s ease-in-out;
}

.back-link:hover {
    background-color: #f1f5f9;
    color: #0f172a;
    border-color: #cbd5e1;
}

#app {
    padding: 1rem;
    background: #f8fafc;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    margin: 0.2rem 0.5rem 1rem 0.5rem;
}

.book-header {
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.book-title {
    font-size: 1.2rem;
    font-weight: 600;
}

.book-author {
    color: #64748b;
    font-size: 0.9rem;
}

/* 各ブロックをフレックスで横並び */
.book-detail__content {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
    color: #64748b;
    font-size: 0.9rem;
    margin-top: 0.25rem;
    margin-bottom: 0.25rem;
}

.book-detail__content p {
    margin: 0;
}

.book-detail__footer {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
    color: #64748b;
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

.comment-title {
    margin-bottom: 0rem;
    border-radius: 4px 4px 0px 0px;
    background: #475569;
    padding: 0.5rem;
    color: #ffffff;
}

.comment {
    margin-top: 0rem;
    margin-bottom: 0.25rem;
    background: #ffffff;
    padding: 0.5rem;
    border-radius: 0px 0px 4px 4px;
}